Removed untyped contructor from ComponentRegistration and add a protected setter.

[castle.git] / MonoRail / Castle.MonoRail.Framework / Helpers / FormHelper.cs

// Copyright 2004-2008 Castle Project - http://www.castleproject.org/
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

namespace Castle.MonoRail.Framework.Helpers
{
        using System;
        using System.Collections;
        using System.Collections.Generic;
        using System.Collections.Specialized;
        using System.Data;
        using System.IO;
        using System.Reflection;
        using System.Text;
        using Configuration;
        using Services;
        using HtmlTextWriter = System.Web.UI.HtmlTextWriter;

        using Castle.Core;
        using Castle.Core.Logging;
        using Castle.MonoRail.Framework;
        using Castle.MonoRail.Framework.Helpers.ValidationStrategy;
        using Castle.MonoRail.Framework.Internal;
        using Castle.Components.Binder;
        using Castle.Components.Validator;

        /// <summary>
        /// Represents all scopes that the <see cref="FormHelper"/>
        /// uses to search for root values
        /// </summary>
        public enum RequestContext
        {
                /// <summary>
                /// All scopes should be searched
                /// </summary>
                All,
                /// <summary>
                /// Only PropertyBag should be searched
                /// </summary>
                PropertyBag,
                /// <summary>
                /// Only Flash should be searched
                /// </summary>
                Flash,
                /// <summary>
                /// Only Session should be searched
                /// </summary>
                Session,
                /// <summary>
                /// Only Request should be searched
                /// </summary>
                Request,
                /// <summary>
                /// Only Params should be searched
                /// </summary>
                Params
        }

        /// <summary>
        /// The FormHelper allows you to output html input elements using the 
        /// conventions necessary to use the DataBinder on the server side. Ultimately it
        /// allows you do to a bi-directional binding -- if used properly.
        /// </summary>
        /// 
        /// <seealso xref="DataBindAttribute"/>
        /// 
        /// <example>
        /// Using simple values:
        /// <para>On the controller:</para>
        /// 
        /// <code>
        /// public void MyAction()
        /// {
        ///             PropertyBag["name"] = "John Doe";
        /// }
        /// </code>
        /// 
        /// <para>On the view (using NVelocity syntax)</para>
        /// 
        /// <code lang="none">
        /// $Form.TextField('name') // Renders an input text with value "John Doe"
        /// </code>
        /// 
        /// <para>
        /// Using complex objects:
        /// </para>
        /// 
        /// <code>
        /// public void MyAction()
        /// {
        ///             PropertyBag["user"] = new User("John Doe");
        /// }
        /// </code>
        /// 
        /// <para>On the view (using NVelocity syntax)</para>
        /// 
        /// <code lang="none">
        /// $Form.TextField('user.name') // Renders an input text with value "John Doe"
        /// </code>
        /// </example>
        /// 
        /// <remarks>
        /// <b>Elements generation</b> <br/>
        /// <para>
        /// <list type="table">
        /// <item>
        ///             <term>Buttons</term>
        ///             <description>
        ///             <see cref="Submit(string)"/> <br/>
        ///             <see cref="Button(string)" /> <br/>
        ///             <see cref="ButtonElement(string)" />
        ///             </description>
        /// </item>
        /// 
        /// <item>
        ///             <term>Select</term>
        ///             <description>
        ///             <see cref="Select(string,IEnumerable)" />
        ///             </description>
        /// </item>
        /// 
        /// <item>
        ///             <term>Text area</term>
        ///             <description>
        ///             <see cref="TextArea(string)" />
        ///             </description>
        /// </item>
        /// 
        /// <item>
        ///             <term>Hidden field</term>
        ///             <description>
        ///             <see cref="HiddenField(string)" /> 
        ///             </description>
        /// </item>
        /// 
        /// <item>
        ///             <term>Checkbox field</term>
        ///             <description>
        ///             <see cref="CheckboxField(string)" />  <br/>
        ///             <see cref="CreateCheckboxList(string,IEnumerable)" /> 
        ///             </description>
        /// </item>
        /// 
        /// <item>
        ///             <term>Radio field</term>
        ///             <description>
        ///             <see cref="RadioField(string,object)" /> 
        ///             </description>
        /// </item>
        /// 
        /// <item>
        ///             <term>File upload</term>
        ///             <description>
        ///             <see cref="FileField(string)" /> 
        ///             </description>
        /// </item>
        /// 
        /// <item>
        ///             <term>Text field</term>
        ///             <description>
        ///             <see cref="TextField(string)" /> <br/>
        ///             <see cref="TextFieldValue(string, object)"/> <br/>
        ///             <see cref="NumberField(string)" /> <br/>
        ///             <see cref="NumberFieldValue(string, object)"/>
        ///             </description>
        /// </item>
        /// 
        /// <item>
        ///             <term>Password field</term>
        ///             <description>
        ///             <see cref="PasswordField(string)" /> <br/>
        ///             <see cref="PasswordNumberField(string)" />
        ///             </description>
        /// </item>
        /// 
        /// <item>
        ///             <term>Labels</term>
        ///             <description>
        ///             <see cref="LabelFor(string,string)" /> <br/>
        ///             <see cref="LabelFor(string,string,IDictionary)"/>
        ///             </description>
        /// </item>
        /// 
        /// </list>
        /// </para>
        /// 
        /// <para>
        /// <b>FormValidation</b> <br/>
        /// The following operations are related to the Form Validation support:
        /// </para>
        /// 
        /// <list type="table">
        /// <item>
        ///             <term><see cref="FormTag(IDictionary)"/> and <see cref="EndFormTag"/> </term>
        ///             <description>Opens/close the form tag. They are required to use the automatic form validation</description>
        /// </item>
        /// <item>
        ///             <term><see cref="DisableValidation"/> </term>
        ///             <description>Disables validation altogether</description>
        /// </item>
        /// <item>
        ///             <term><see cref="UseWebValidatorProvider"/> </term>
        ///             <description>Sets a custom Browser validator provider</description>
        /// </item>
        /// <item>
        ///             <term><see cref="UsePrototypeValidation"/> </term>
        ///             <description>Configures the helper to use the prototype easy field validation. Must be invoked before FormTag</description>
        /// </item>
        /// <item>
        ///             <term><see cref="UsefValidate"/> </term>
        ///             <description>Configures the helper to use the fValidate. Deprecated.</description>
        /// </item>
        /// <item>
        ///             <term><see cref="UseZebdaValidation"/> </term>
        ///             <description>Configures the helper to use the Zebda. Must be invoked before FormTag</description>
        /// </item>
        /// </list>
        /// 
        /// <para>
        /// <b>Mask support</b>. <br/>
        /// For most elements, you can use 
        /// the entries <c>mask</c> and optionally <c>mask_separator</c> to define a 
        /// mask for your inputs. Kudos to mordechai Sandhaus - 52action.com
        /// </para>
        /// 
        /// <para>
        /// For example: mask='2,5',mask_separator='/' will mask the content to '12/34/1234'
        /// </para>
        /// </remarks>
        public class FormHelper : AbstractHelper, IServiceEnabledComponent
        {
                /// <summary>
                /// Common property flags for reflection
                /// </summary>
                protected static readonly BindingFlags PropertyFlags = BindingFlags.GetProperty|BindingFlags.Public|BindingFlags.Instance|BindingFlags.IgnoreCase;
                /// <summary>
                /// Common property flags for reflection (with declared only)
                /// </summary>
                protected static readonly BindingFlags PropertyFlags2 = BindingFlags.GetProperty|BindingFlags.Public|BindingFlags.Instance|BindingFlags.IgnoreCase|BindingFlags.DeclaredOnly;
                /// <summary>
                /// Common field flags for reflection
                /// </summary>
                protected static readonly BindingFlags FieldFlags = BindingFlags.GetField|BindingFlags.Public|BindingFlags.Instance|BindingFlags.IgnoreCase;

                private int formCount;
                private string currentFormId;
                private bool isValidationDisabled;
                private readonly Stack objectStack = new Stack();
                private BrowserValidationConfiguration validationConfig;
                private IBrowserValidatorProvider validatorProvider = new PrototypeWebValidator();
                private IValidatorRegistry validatorRegistry;
                private ValidatorRunner validatorRunner;

                #region Constructors
                /// <summary>
                /// Initializes a new instance of the <see cref="FormHelper"/> class.
                /// </summary>
                public FormHelper()
                {
                        validatorRegistry = new CachedValidationRegistry();
                        validatorRunner = new ValidatorRunner(false, validatorRegistry);
                }

                /// <summary>
                /// Initializes a new instance of the <see cref="FormHelper"/> class.
                /// setting the Controller, Context and ControllerContext.
                /// </summary>
                /// <param name="engineContext">The engine context.</param>
                public FormHelper(IEngineContext engineContext) : base(engineContext)
                {
                        validatorRegistry = new CachedValidationRegistry();
                        validatorRunner = new ValidatorRunner(false, validatorRegistry);
                }

                #endregion

                /// <summary>
                /// Logger instance
                /// </summary>
                protected static ILogger logger = NullLogger.Instance;

                #region IServiceEnabledComponent implementation

                /// <summary>
                /// Invoked by the framework in order to give a chance to
                /// obtain other services
                /// </summary>
                /// <param name="provider">The service proviver</param>
                public virtual void Service(IServiceProvider provider)
                {
                        ILoggerFactory loggerFactory = (ILoggerFactory) provider.GetService(typeof(ILoggerFactory));

                        if (loggerFactory != null)
                        {
                                logger = loggerFactory.Create(typeof(FormHelper));
                        }

                        IMonoRailConfiguration config = (IMonoRailConfiguration) provider.GetService(typeof(IMonoRailConfiguration));

                        if (config != null)
                        {
                                LibraryConfiguration jsLibConfig = config.JSGeneratorConfiguration.DefaultLibrary;

                                if (jsLibConfig != null)
                                {
                                        if (jsLibConfig.BrowserValidatorProvider != null)
                                        {
                                                validatorProvider = (IBrowserValidatorProvider)
                                                        Activator.CreateInstance(jsLibConfig.BrowserValidatorProvider);
                                        }
                                }
                        }

                        validatorRegistry = (IValidatorRegistry) provider.GetService(typeof(IValidatorRegistry));

                        if (validatorRegistry != null)
                        {
                                validatorRunner = new ValidatorRunner(false, validatorRegistry);
                        }
                        else
                        {
                                validatorRunner = new ValidatorRunner(false, new CachedValidationRegistry());
                        }
                }

                #endregion

                /// <summary>
                /// Gets or sets the validator provider.
                /// </summary>
                /// <value>The validator provider.</value>
                public IBrowserValidatorProvider ValidatorProvider
                {
                        get { return validatorProvider; }
                        set { validatorProvider = value; }
                }

                /// <summary>
                /// Gets or sets the validator runner.
                /// </summary>
                /// <value>The validator runner.</value>
                public ValidatorRunner ValidatorRunner
                {
                        get { return validatorRunner; }
                        set { validatorRunner = value; }
                }

                /// <summary>
                /// Renders a Javascript library inside a single script tag.
                /// </summary>
                /// <returns></returns>
                public virtual string InstallScripts()
                {
                        return RenderScriptBlockToSource("/MonoRail/Files/FormHelperScript");
                }

                #region FormTag related

                /// <summary>
                /// Creates a form tag based on the parameters.
                /// <para>
                /// Javascript validation can also be bound to 
                /// the form and|or elements nested as long as the helper is 
                /// able to reach the <see cref="Type"/> of the object used on your view code
                /// </para>
                /// <para>
                /// The action attribute generation will use <see cref="UrlHelper"/>
                /// </para>
                /// </summary>
                /// 
                /// <seealso cref="DefaultUrlBuilder.BuildUrl(UrlInfo,IDictionary)"/>
                /// 
                /// <example>
                /// 
                /// <code lang="none">
                /// $Form.FormTag("%{action='Save',id='productform'}")
                /// </code>
                /// 
                /// Outputs:
                /// 
                /// <code lang="xml">
                /// &lt;form method='post' action='/[appdir]/[controller]/Save.[extension]' id='productform'&gt;
                /// </code>
                ///
                /// </example>
                /// 
                /// <remarks>
                /// The parameters are used to build a url and also to form the tag. For notes on the url 
                /// see <see cref="DefaultUrlBuilder.BuildUrl(UrlInfo,IDictionary)"/>. The other parameters supported 
                /// follows
                /// 
                /// <list type="table">
                /// <term>
                ///             <term>noaction</term>
                ///             <description>boolean. Disables the generation of an action</description>
                /// </term>
                /// <term>
                ///             <term>method</term>
                ///             <description>string. The http method to use. Defaults to <c>post</c></description>
                /// </term>
                /// <term>
                ///             <term>id</term>
                ///             <description>string. The form id.</description>
                /// </term>
                /// </list>
                /// 
                /// More parameters can be accepted depending on the form validation strategy you are using (if any).
                /// 
                /// </remarks>
                /// 
                /// <param name="parameters">The parameters for the tag or for action and form validation generation.</param>
                /// <returns></returns>
                public virtual string FormTag(IDictionary parameters)
                {
                        string url = null;

                        // Creates action attribute
                        if (CommonUtils.ObtainEntryAndRemove(parameters, "noaction", "false") == "false")
                        {
                                url = UrlHelper.For(parameters);
                        }

                        return FormTag(url, parameters);
                }

                /// <summary>
                /// Creates a form tag based on the parameters.
                /// <para>
                /// Javascript validation can also be bound to 
                /// the form and|or elements nested as long as the helper is 
                /// able to reach the <see cref="Type"/> of the object used on your view code
                /// </para>
                /// <para>
                /// The action attribute generation will use <see cref="UrlHelper"/>
                /// </para>
                /// </summary>
                /// 
                /// <example>
                /// 
                /// <code lang="none">
                /// $Form.FormTag('mytarget.castle', "%{id='productform'}")
                /// </code>
                /// 
                /// Outputs:
                /// 
                /// <code lang="xml">
                /// &lt;form method='post' action='mytarget.castle' id='productform'&gt;
                /// </code>
                ///
                /// </example>
                /// 
                /// <remarks>
                /// The following parameters are accepted.
                /// 
                /// <list type="table">
                /// <term>
                ///             <term>method</term>
                ///             <description>string. The http method to use. Defaults to <c>post</c></description>
                /// </term>
                /// <term>
                ///             <term>id</term>
                ///             <description>string. The form id.</description>
                /// </term>
                /// </list>
                /// 
                /// More parameters can be accepted depending on the form validation strategy you are using (if any).
                /// 
                /// </remarks>
                /// 
                /// <param name="url">The hardcoded url.</param>
                /// <param name="parameters">The parameters for the tag or for action and form validation generation.</param>
                /// <returns></returns>
                public virtual string FormTag(string url, IDictionary parameters)
                {
                        string method = CommonUtils.ObtainEntryAndRemove(parameters, "method", "post");
                        currentFormId = CommonUtils.ObtainEntryAndRemove(parameters, "id", "form" + ++formCount);

                        validationConfig = validatorProvider.CreateConfiguration(parameters);

                        string afterFormTag = IsValidationEnabled ? 
                                validationConfig.CreateAfterFormOpened(currentFormId) : 
                                String.Empty;

                        string formContent;

                        if (url != null)
                        {
                                formContent = "<form action='" + url + "' method='" + method + "' " +
                                        "id='" + currentFormId + "' " + GetAttributes(parameters) + ">";
                        }
                        else
                        {
                                formContent = "<form method='" + method + "' id='" + currentFormId + "' " + GetAttributes(parameters) + ">";
                        }

                        return formContent + afterFormTag;
                }

                /// <summary>
                /// Generate Ajax form tag for ajax based form submission. Experimental.
                /// </summary>
                /// <param name="parameters"></param>
                /// <returns></returns>
                public virtual string AjaxFormTag(IDictionary parameters)
                {
                        currentFormId = CommonUtils.ObtainEntryAndRemove(parameters, "id", "form" + ++formCount);
                        
                        validationConfig = validatorProvider.CreateConfiguration(parameters);

                        string afterFormTag = IsValidationEnabled ?
                                validationConfig.CreateAfterFormOpened(currentFormId) :
                                String.Empty;

                        string url = UrlHelper.For(parameters);

                        parameters["form"] = true;

                        if (parameters.Contains("onsubmit"))
                        {
                                string onSubmitFunc = CommonUtils.ObtainEntryAndRemove(parameters, "onsubmit");
                                //remove return to make it compatible for ajax condition
                                if (onSubmitFunc.StartsWith("return ", StringComparison.InvariantCultureIgnoreCase))
                                {
                                        onSubmitFunc = onSubmitFunc.Substring(7);
                                }
                                if (onSubmitFunc.EndsWith(";", StringComparison.InvariantCultureIgnoreCase))
                                {
                                        onSubmitFunc = onSubmitFunc.Remove(onSubmitFunc.Length - 1);
                                }
                                string conditionFunc = CommonUtils.ObtainEntryAndRemove(parameters, "condition", string.Empty);
                                if (!string.IsNullOrEmpty(conditionFunc))
                                {
                                        conditionFunc += " && ";
                                }
                                conditionFunc += onSubmitFunc;
                                
                                parameters["condition"] = conditionFunc;
                        }
                        bool isMethodAssigned = parameters.Contains("method");

                        string method = CommonUtils.ObtainEntryAndRemove(parameters, "method", "post");
                        
                        parameters["url"] = url;
                        
                        // reassign method so in case if there is no value the default is assigned.
                        
                        if (isMethodAssigned)
                        {
                                parameters["method"] = method;
                        }

                        String remoteFunc = new AjaxHelper().RemoteFunction(parameters);

                        string formContent = String.Format("<form id='{1}' method='{2}' {3} onsubmit=\"{0}; return false;\" enctype=\"multipart/form-data\">", remoteFunc, currentFormId, method,GetAttributes(parameters));

                        return formContent + afterFormTag;
                }

                /// <summary>
                /// Renders an end form element.
                /// </summary>
                /// <remarks>
                /// Should be used if you are using form validation. Some validation approaches
                /// uses the end form before or after appending a javascript snippet.
                /// </remarks>
                /// <returns></returns>
                public virtual string EndFormTag()
                {
                        string beforeEndTag = string.Empty;

                        if (validationConfig != null)
                        {
                                beforeEndTag = IsValidationEnabled ?
                                        validationConfig.CreateBeforeFormClosed(currentFormId) :
                                        String.Empty;
                        }
                        
                        return beforeEndTag + "</form>";
                }

                #endregion

                #region Object scope related

                /// <summary>
                /// Pushes the specified target. Experimental.
                /// </summary>
                /// <param name="target">The target.</param>
                public virtual void Push(string target)
                {
                        Push(target, null);
                }

                /// <summary>
                /// Pushes the specified target. Experimental.
                /// </summary>
                /// <param name="target">The target.</param>
                /// <param name="parameters">The parameters.</param>
                public virtual void Push(string target, IDictionary parameters)
                {
                        string disableValidation = CommonUtils.ObtainEntryAndRemove(parameters, "disablevalidation", "false");
                        object value = ObtainValue(target);

                        if (value != null)
                        {
                                objectStack.Push(new FormScopeInfo(target, disableValidation != "true"));
                        }
                        else
                        {
                                value = ObtainValue(target + "type");

                                if (value != null)
                                {
                                        objectStack.Push(new FormScopeInfo(target, disableValidation != "true"));
                                }
                                else
                                {
                                        throw new ArgumentException("target could not be evaluated during Push operation. Target: " + target);
                                }
                        }
                }

                /// <summary>
                /// Pops this instance. Experimental.
                /// </summary>
                public virtual void Pop()
                {
                        objectStack.Pop();
                }

                #endregion

                #region Submit and Button related

                /// <summary>
                /// Generates an input submit element.
                /// </summary>
                /// <param name="value">The value/caption for the button.</param>
                /// <returns>The element tag</returns>
                public virtual string Submit(string value)
                {
                        return Submit(value, null);
                }

                /// <summary>
                /// Generates an input submit element.
                /// </summary>
                /// <param name="value">The value/caption for the button.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The element tag</returns>
                public virtual string Submit(string value, IDictionary attributes)
                {
                        return CreateInputElement("submit", value, attributes);
                }

                /// <summary>
                /// Generates an graphical submit element.
                /// </summary>
                /// <param name="imgsrc">The path the image file.</param>
                /// <param name="alttext">The alt text displayed by screenreaders, or when images are not enabled.</param>
                /// <returns>The element tag</returns>
                public virtual string ImageSubmit(string imgsrc, string alttext)
                {
                        return ImageSubmit(imgsrc, alttext, null);
                }

                /// <summary>
                /// Generates an input submit element.
                /// </summary>
                /// <param name="imgsrc">The path the image file.</param>
                /// <param name="alttext">The alt text displayed by screenreaders, or when images are not enabled.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The element tag</returns>
                public virtual string ImageSubmit(string imgsrc, string alttext, IDictionary attributes)
                {
                        attributes = attributes != null ? attributes : new Hashtable();
                        attributes["src"] = imgsrc;
                        attributes["alt"] = alttext;
                        return CreateInputElement("image", alttext, attributes);
                }
                
                /// <summary>
                /// Generates an input button element.
                /// </summary>
                /// <param name="value">The value.</param>
                /// <returns>The element tag</returns>
                public virtual string Button(string value)
                {
                        return Button(value, null);
                }

                /// <summary>
                /// Generates an input button element.
                /// </summary>
                /// <param name="value">The value.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The element tag</returns>
                public virtual string Button(string value, IDictionary attributes)
                {
                        return CreateInputElement("button", value, attributes);
                }

                /// <summary>
                /// Creates a basic button element of type submit.
                /// </summary>
                /// <param name="innerText">The inner text of the button element.</param>
                /// <returns>The generated button element.</returns>
                public virtual string ButtonElement(string innerText)
                {
                        return ButtonElement(innerText, "submit", null);
                }

                /// <summary>
                /// Creates a basic button element of the specified type.
                /// </summary>
                /// <param name="innerText">The inner text of the button element.</param>
                /// <param name="type">The type of the button.</param>
                /// <returns>The generated button element.</returns>
                public virtual string ButtonElement(string innerText, string type)
                {
                        return ButtonElement(innerText, type, null);
                }

                /// <summary>
                /// Creates a basic button element of the specified type and with specified attributes.
                /// </summary>
                /// <param name="innerText">The inner text of the button element.</param>
                /// <param name="type">The type of the button.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated button element.</returns>
                public virtual string ButtonElement(string innerText, string type, IDictionary attributes)
                {
                        return String.Format("<button type=\"{0}\" {1}>{2}</button>", type, GetAttributes(attributes), innerText);
                }

                #endregion

                #region TextFieldValue

                /// <summary>
                /// Generates an input text form element
                /// with the supplied value
                /// </summary>
                /// <param name="target">The string to be used to create the element name.</param>
                /// <param name="value">Value to supply to the element (instead of querying the target)</param>
                /// <returns>The generated form element</returns>
                public string TextFieldValue(string target, object value)
                {
                        return TextFieldValue(target, value, null);
                }

                /// <summary>
                /// Generates an input text form element
                /// with the supplied value
                /// </summary>
                /// <param name="target">The string to be used to create the element name.</param>
                /// <param name="value">Value to supply to the element (instead of querying the target)</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public string TextFieldValue(string target, object value, IDictionary attributes)
                {
                        return CreateInputElement("text", target, value, attributes);
                }

                #endregion

                #region TextField

                /// <summary>
                /// Generates an input text element.
                /// <para>
                /// The value is extracted from the target (if available)
                /// </para>
                /// </summary>
                /// 
                /// <example>
                /// The following example assumes that an entry <c>username</c> exists on the
                /// <see cref="Controller.PropertyBag"/> or <see cref="Controller.Flash"/> or <see cref="Controller.Session"/>
                /// 
                /// <code lang="none">
                /// $Form.TextField('username')
                /// </code>
                /// Outputs:
                /// <code lang="xml">
                /// &lt;input type='text' name='username' id='username' value='John Doe' /&gt;
                /// </code>
                /// 
                /// <para>
                /// The following example assumes that an entry <c>user</c> exists on the
                /// <see cref="Controller.PropertyBag"/> or <see cref="Controller.Flash"/> or <see cref="Controller.Session"/>
                /// </para>
                /// 
                /// <code lang="none">
                /// $Form.TextField('user.name')
                /// </code>
                /// Outputs:
                /// <code lang="xml">
                /// &lt;input type='text' name='user.name' id='user_name' value='John Doe' /&gt;
                /// </code>
                /// </example>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <returns>The generated form element</returns>
                public virtual string TextField(string target)
                {
                        return TextField(target, null);
                }

                /// <summary>
                /// Generates an input text element.
                /// <para>
                /// The value is extracted from the target (if available)
                /// </para>
                /// </summary>
                /// 
                /// <seealso cref="TextField(string)"/>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string TextField(string target, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        object value = ObtainValue(target);

                        ApplyValidation(InputElementType.Text, target, ref attributes);

                        return CreateInputElement("text", target, value, attributes);
                }

                /// <summary>
                /// Combines <see cref="AjaxHelper.InputTextWithAutoCompletion(string,string,IDictionary,IDictionary)"/>
                /// with <see cref="TextField(string,IDictionary)"/> to achieve an TextField that offers
                /// both input completion and databinding support.
                /// </summary>
                /// <param name="target">The target of the text field (analogous to <see cref="TextField(string,IDictionary)"/>)</param>
                /// <param name="url">The url to call for completion options (analogous to <see cref="AjaxHelper.InputTextWithAutoCompletion(string,string,IDictionary,IDictionary)"/>)</param>
                /// <param name="tagAttributes">The attributes to apply to the text input field. If this dictionary does not contain a value for browser-based autocompletion (autocomplete="off|on"), it will default to "off" to prevent interference of AJAX-based and browser-based autocompletion.</param>
                /// <param name="completionOptions">The options for the AJAX-call analogous to <see cref="AjaxHelper.InputTextWithAutoCompletion(string,string,IDictionary,IDictionary)"/>.</param>
                /// <returns>The generated form elements.</returns>
                /// <remarks>Please note that this function requires Ajax scripts (Prototype/Scriptaculous)</remarks>
                public virtual string TextFieldAutoComplete(string target, string url, IDictionary tagAttributes, IDictionary completionOptions)
                {
                        if (!tagAttributes.Contains("autocomplete")) tagAttributes.Add("autocomplete", "off");

                        StringBuilder sb = new StringBuilder();
                        sb.Append(TextField(target, tagAttributes));

                        string textFieldId = CreateHtmlId(tagAttributes, target);
                        sb.AppendFormat("<div id=\"{0}\" class=\"auto_complete\"></div>", textFieldId + "autocomplete");
                        sb.Append(new AjaxHelper().AutoCompleteInputText(textFieldId, url, completionOptions));

                        return sb.ToString();
                }


                #endregion

                #region FilteredTextField

                /// <summary>
                /// Generates an input text element with a javascript that prevents the 
                /// chars listed in the forbid attribute from being entered.
                /// </summary>
                /// <para>
                /// You must pass an <c>forbid</c> value through the dictionary.
                /// It must be a comma separated list of chars that cannot be accepted on the field. 
                /// For example:
                /// </para>
                /// <code>
                /// FormHelper.FilteredTextField("product.price", {forbid='46'})
                /// </code>
                /// In this case the key code 46 (period) will not be accepted on the field.
                /// <para>
                /// The value is extracted from the target (if available).
                /// </para>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element.</returns>
                /// <remarks>
                /// You must invoke <see cref="FormHelper.InstallScripts"/> before using it.
                /// </remarks>
                public virtual string FilteredTextField(string target, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        object value = ObtainValue(target);

                        attributes = attributes != null ? attributes : new Hashtable();

                        ApplyFilterOptions(attributes);
                        ApplyValidation(InputElementType.Text, target, ref attributes);

                        return CreateInputElement("text", target, value, attributes);
                }

                #endregion

                #region NumberField

                /// <summary>
                /// Generates an input text element with a javascript that prevents
                /// chars other than numbers from being entered.
                /// <para>
                /// The value is extracted from the target (if available)
                /// </para>
                /// </summary>
                /// 
                /// <seealso cref="InstallScripts"/>
                /// <seealso cref="NumberField(string,IDictionary)"/>
                /// 
                /// <remarks>
                /// You must include the formhelper javascript functions to use the NumberField. 
                /// See <see cref="InstallScripts"/>
                /// </remarks>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <returns>The generated form element</returns>
                public virtual string NumberField(string target)
                {
                        return NumberField(target, null);
                }

                /// <summary>
                /// Generates an input text element with a javascript that prevents
                /// chars other than numbers from being entered.
                /// <para>
                /// The value is extracted from the target (if available)
                /// </para>
                /// </summary>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                /// 
                /// <remarks>
                /// You must include the formhelper javascript functions to use the NumberField. 
                /// See <see cref="InstallScripts"/>
                /// <para>
                /// You can optionally pass an <c>exceptions</c> value through the dictionary.
                /// It must be a comma separated list of chars that can be accepted on the field. 
                /// For example:
                /// </para>
                /// <code>
                /// FormHelper.NumberField("product.price", {exceptions='13,10,11'})
                /// </code>
                /// In this case the key codes 13, 10 and 11 will be accepted on the field.
                /// <para>
                /// You can aslo optionally pass an <c>forbid</c> value through the dictionary.
                /// It must be a comma separated list of chars that cannot be accepted on the field. 
                /// For example:
                /// </para>
                /// <code>
                /// FormHelper.NumberField("product.price", {forbid='46'})
                /// </code>
                /// In this case the key code 46 (period) will not be accepted on the field.
                /// </remarks>
                public virtual string NumberField(string target, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        object value = ObtainValue(target);

                        attributes = attributes != null ? attributes : new Hashtable();

                        ApplyNumberOnlyOptions(attributes);
                        ApplyValidation(InputElementType.Text, target, ref attributes);

                        return CreateInputElement("text", target, value, attributes);
                }

                #endregion

                #region NumberFieldValue

                /// <summary>
                /// Generates an input text element with a javascript that prevents
                /// chars other than numbers from being entered. The value is not gathered 
                /// from the context, instead you specify it on the second argument
                /// </summary>
                /// 
                /// <seealso cref="InstallScripts"/>
                /// <seealso cref="NumberField(string,IDictionary)"/>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="value">The current value to output.</param>
                /// <returns>The generated form element</returns>
                /// 
                /// <remarks>
                /// You must include the formhelper javascript functions to use the NumberField. 
                /// See <see cref="InstallScripts"/>
                /// </remarks>
                public virtual string NumberFieldValue(string target, object value)
                {
                        return NumberFieldValue(target, value, null);
                }

                /// <summary>
                /// Generates an input text element with a javascript that prevents
                /// chars other than numbers from being entered. The value is not gathered 
                /// from the context, instead you specify it on the second argument
                /// </summary>
                /// 
                /// <seealso cref="InstallScripts"/>
                /// <seealso cref="NumberField(string,IDictionary)"/>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="value">The current value to output.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                /// 
                /// <remarks>
                /// You must include the formhelper javascript functions to use the NumberField. 
                /// See <see cref="InstallScripts"/>
                /// </remarks>
                public virtual string NumberFieldValue(string target, object value, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        attributes = attributes ?? new Hashtable();

                        ApplyNumberOnlyOptions(attributes);
                        ApplyValidation(InputElementType.Text, target, ref attributes);

                        return CreateInputElement("text", target, value, attributes);
                }

                #endregion

                #region TextArea

                /// <summary>
                /// Generates a textarea element.
                /// <para>
                /// The value is extracted from the target (if available)
                /// </para>
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <returns>The generated form element</returns>
                public virtual string TextArea(string target)
                {
                        return TextArea(target, null);
                }

                /// <summary>
                /// Generates a textarea element.
                /// <para>
                /// The value is extracted from the target (if available)
                /// </para>
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string TextArea(string target, IDictionary attributes)
                {
                        string targetForValue = RewriteTargetIfWithinObjectScope(target);
                        object value = ObtainValue(targetForValue);
                        return TextAreaValue(target, value, attributes);
                }

                /// <summary>
                /// Generates a textarea element with a specified value.
                /// </summary>
                /// <param name="target">The target to base the element name on.</param>
                /// <param name="value">The value to apply to the field.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string TextAreaValue(string target, object value, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        value = value == null ? "" : HtmlEncode(value.ToString());

                        string id = CreateHtmlId(target);

                        ApplyValidation(InputElementType.Text, target, ref attributes);

                        return String.Format("<textarea id=\"{0}\" name=\"{1}\" {2}>{3}</textarea>",
                                id, target, GetAttributes(attributes), FormatIfNecessary(value, attributes));
                }

                #endregion

                #region PasswordField

                /// <summary>
                /// Generates a password input field.
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <returns>The generated form element</returns>
                public virtual string PasswordField(string target)
                {
                        return PasswordField(target, null);
                }

                /// <summary>
                /// Generates a password input field.
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string PasswordField(string target, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        object value = ObtainValue(target);

                        ApplyValidation(InputElementType.Text, target, ref attributes);

                        return CreateInputElement("password", target, value, attributes);
                }

                #endregion

                #region PasswordNumberField

                /// <summary>
                /// Generates an input password element with a javascript that prevents
                /// chars other than numbers from being entered.
                /// <para>
                /// The value is extracted from the target (if available)
                /// </para>
                /// </summary>
                /// <remarks>
                /// You must invoke <see cref="FormHelper.InstallScripts"/> before using it
                /// </remarks>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <returns>The generated form element</returns>
                public virtual string PasswordNumberField(string target)
                {
                        return PasswordNumberField(target, null);
                }

                /// <summary>
                /// Generates an input password element with a javascript that prevents
                /// chars other than numbers from being entered.
                /// <para>
                /// The value is extracted from the target (if available)
                /// </para>
                /// <para>
                /// You can optionally pass an <c>exceptions</c> value through the dictionary.
                /// It must be a comma separated list of chars that can be accepted on the field. 
                /// For example:
                /// </para>
                /// <code>
                /// FormHelper.NumberField("product.price", {exceptions='13,10,11'})
                /// </code>
                /// In this case the key codes 13, 10 and 11 will be accepted on the field.
                /// <para>
                /// You can aslo optionally pass an <c>forbid</c> value through the dictionary.
                /// It must be a comma separated list of chars that cannot be accepted on the field. 
                /// For example:
                /// </para>
                /// <code>
                /// FormHelper.NumberField("product.price", {forbid='46'})
                /// </code>
                /// In this case the key code 46 (period) will not be accepted on the field.
                /// </summary>
                /// <remarks>
                /// You must invoke <see cref="FormHelper.InstallScripts"/> before using it
                /// </remarks>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string PasswordNumberField(string target, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        object value = ObtainValue(target);

                        attributes = attributes != null ? attributes : new Hashtable();

                        ApplyNumberOnlyOptions(attributes);
                        ApplyValidation(InputElementType.Text, target, ref attributes);

                        return CreateInputElement("password", target, value, attributes);
                }

                #endregion

                #region LiteralFor

                ///<summary>Returns the value for specified target with no additional markup. If no value is obtained
                /// an empty string is returned.
                ///</summary>
                ///<param name="target">The object to get the value from.</param>
                ///<returns>The value or an empty string if none is found.</returns>
                public virtual string LiteralFor(string target)
                {
                        target = RewriteTargetIfWithinObjectScope(target);
                        object value = ObtainValue(target);
                        if (value == null)
                        {
                                return string.Empty;
                        }
                        return value.ToString();
                }

                #endregion

                #region LabelFor

                /// <summary>
                /// Generates a label element.
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="label">Legend</param>
                /// <returns>The generated form element</returns>
                public virtual string LabelFor(string target, string label)
                {
                        return LabelFor(target, label, null);
                }

                /// <summary>
                /// Generates a label element.
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="label">Legend</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string LabelFor(string target, string label, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        string id = CreateHtmlId(attributes, target);

                        StringBuilder sb = new StringBuilder();
                        StringWriter sbWriter = new StringWriter(sb);
                        HtmlTextWriter writer = new HtmlTextWriter(sbWriter);

                        writer.WriteBeginTag("label");
                        writer.WriteAttribute("for", id);
                        string strAttributes = GetAttributes(attributes);
                        if (strAttributes != String.Empty)
                        {
                                writer.Write(HtmlTextWriter.SpaceChar);
                        }

                        writer.Write(strAttributes);
                        writer.Write(HtmlTextWriter.TagRightChar);
                        writer.Write(label);
                        writer.WriteEndTag("label");

                        return sbWriter.ToString();
                }

                #endregion

                #region HiddenField

                /// <summary>
                /// Generates a hidden form element.
                /// <para>
                /// The value is extracted from the target (if available)
                /// </para>
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <returns>The generated form element</returns>
                public virtual string HiddenField(string target)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        object value = ObtainValue(target);

                        return CreateInputElement("hidden", target, value, null);
                }

                /// <summary>
                /// Generates a hidden form element with the specified value
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="value">The value for the hidden field</param>
                /// <returns>The generated form element</returns>
                public virtual string HiddenField(string target, object value)
                {
                        return CreateInputElement("hidden", target, value, null);
                }
                
                /// <summary>
                /// Generates a hidden form element.
                /// <para>
                /// The value is extracted from the target (if available)
                /// </para>
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string HiddenField(string target, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        object value = ObtainValue(target);
                        
                        string id = CreateHtmlId(attributes, target);
                        
                        value = value != null ? value : String.Empty;

                        return CreateInputElement("hidden", id, target, value.ToString(), attributes);
                }
                
                /// <summary>
                /// Generates a hidden form element with the specified value
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="value">The value for the hidden field</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string HiddenField(string target, object value, IDictionary attributes)
                {
                        return CreateInputElement("hidden", target, value, attributes);
                }

                #endregion

                #region CheckboxList

                /// <summary>
                /// Creates a <see cref="CheckboxList"/> instance
                /// which is enumerable. For each interaction you can invoke
                /// <see cref="CheckboxList.Item()"/> which will correctly render
                /// a checkbox input element for the current element on the supplied set (<c>dataSource</c>).
                /// <para>
                /// The enumerable item will be an element of the <c>dataSource</c>.
                /// </para>
                /// If the <c>dataSource</c>
                /// elements are complex objects (ie not string or primitives), 
                /// supply the parameters <c>value</c> and <c>text</c> to the dictionary to make
                /// the helper use the specified properties to extract the <c>option</c> value and content respectively.
                /// <para>
                /// Usually both the <c>target</c> and obviously the <c>dataSource</c> are sets
                /// with multiple items. The element types tend to be the same. If 
                /// they are not, you might have to specify the <c>suffix</c> parameters on 
                /// the <c>attributes</c> as it would not be inferred.
                /// </para>
                /// </summary>
                /// 
                /// <example>
                /// Consider the following action code:
                /// <code>
                /// public void Index()
                /// {
                ///     // data source
                ///     PropertyBag["primenumbers"] = new int[] { 2, 3, 5, 7, 11, 13, 17, 19, 23 };
                ///     
                ///     // initial selection
                ///     PropertyBag["selectedPrimes"] = new int[] { 11, 19 };
                /// }
                /// </code>
                /// 
                /// And the respective view code
                /// 
                /// <code lang="none">
                /// #set($items = $FormHelper.CreateCheckboxList("selectedPrimes", $primenumbers))
                /// 
                /// #foreach($elem in $items)
                ///   $items.Item()  $elem 
                /// #end
                /// </code>
                /// 
                /// That will generates the following html:
                /// 
                /// <code lang="none">
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;selectedPrimes_0_&quot; name=&quot;selectedPrimes[0]&quot; value=&quot;2&quot; /&gt;  2   
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;selectedPrimes_1_&quot; name=&quot;selectedPrimes[1]&quot; value=&quot;3&quot; /&gt;  3   
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;selectedPrimes_2_&quot; name=&quot;selectedPrimes[2]&quot; value=&quot;5&quot; /&gt;  5   
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;selectedPrimes_3_&quot; name=&quot;selectedPrimes[3]&quot; value=&quot;7&quot; /&gt;  7   
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;selectedPrimes_4_&quot; name=&quot;selectedPrimes[4]&quot; value=&quot;11&quot; checked=&quot;checked&quot; /&gt;  11  
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;selectedPrimes_5_&quot; name=&quot;selectedPrimes[5]&quot; value=&quot;13&quot; /&gt;  13   
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;selectedPrimes_6_&quot; name=&quot;selectedPrimes[6]&quot; value=&quot;17&quot; /&gt;  17   
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;selectedPrimes_7_&quot; name=&quot;selectedPrimes[7]&quot; value=&quot;19&quot; checked=&quot;checked&quot; /&gt;  19  
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;selectedPrimes_8_&quot; name=&quot;selectedPrimes[8]&quot; value=&quot;23&quot; /&gt;  23   
                /// </code>
                /// 
                /// <para>
                /// To customize the id, you can call the <see cref="CheckboxList.Item(string)"/> overload:
                /// </para>
                /// 
                /// <code lang="none">
                /// #set($items = $FormHelper.CreateCheckboxList("selectedPrimes", $primenumbers))
                /// 
                /// #foreach($elem in $items)
                ///   $items.Item("myId${velocityCount}") $Form.LabelFor("myId${velocityCount}", $elem.ToString()) <br/>
                /// #end
                /// </code>
                /// </example>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="dataSource">The set of available elements</param>
                /// <returns>The generated form element</returns>
                public virtual CheckboxList CreateCheckboxList(string target, IEnumerable dataSource)
                {
                        return CreateCheckboxList(target, dataSource, null);
                }

                /// <summary>
                /// Creates a <see cref="CheckboxList"/> instance
                /// which is enumerable. For each interaction you can invoke
                /// <see cref="CheckboxList.Item()"/> which will correctly render
                /// a checkbox input element for the current element on the supplied set (<c>dataSource</c>).
                /// <para>
                /// The enumerable item will be an element of the <c>dataSource</c>.
                /// </para>
                /// If the <c>dataSource</c>
                /// elements are complex objects (ie not string or primitives), 
                /// supply the parameters <c>value</c> and <c>text</c> to the dictionary to make
                /// the helper use the specified properties to extract the <c>option</c> value and content respectively.
                /// <para>
                /// Usually both the <c>target</c> and obviously the <c>dataSource</c> are sets
                /// with multiple items. The element types tend to be the same. If 
                /// they are not, you might have to specify the <c>suffix</c> parameters on 
                /// the <c>attributes</c> as it would not be inferred.
                /// </para>
                /// </summary>
                /// 
                /// <seealso cref="CreateCheckboxList(string,IEnumerable)"/>
                ///
                /// <example>
                /// Consider the following action code:
                /// <code>
                /// public void Index()
                /// {
                ///             Category[] categories = new Category[] { new Category(1, "Music"), new Category(2, "Humor"), new Category(3, "Politics")  };
                ///             PropertyBag["categories"] = categories; // datasource
                /// 
                ///     Blog blog = new Blog();
                ///     blog.Categories = new Category[] { new Category(2, "Humor") }; // initial selection
                ///             PropertyBag["blog"] = blog;
                /// }
                /// </code>
                /// 
                /// And the respective view code
                /// 
                /// <code lang="none">
                /// #set($items = $Form.CreateCheckboxList("blog.categories", $categories, "%{value='Id'}"))
                /// 
                /// #foreach($elem in $items)
                ///   $items.Item()  $elem  
                /// #end
                /// </code>
                /// 
                /// That will generates the following html:
                /// 
                /// <code lang="none">
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;blog_categories_0_&quot; name=&quot;blog.categories[0].Id&quot; value=&quot;1&quot; /&gt;  Music   
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;blog_categories_1_&quot; name=&quot;blog.categories[1].Id&quot; value=&quot;2&quot; checked=&quot;checked&quot; /&gt;  Humor  
                ///   &lt;input type=&quot;checkbox&quot; id=&quot;blog_categories_2_&quot; name=&quot;blog.categories[2].Id&quot; value=&quot;3&quot; /&gt;  Politics  
                /// </code>
                /// 
                /// </example>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="dataSource">The set of available elements</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual CheckboxList CreateCheckboxList(string target, IEnumerable dataSource, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        object value = ObtainValue(target);
                        
                        return new CheckboxList(this, target, value, dataSource, attributes);
                }
                
                /// <summary>
                /// Outputs a checkbox element (for internal use)
                /// </summary>
                /// <param name="index"></param>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="suffix"></param>
                /// <param name="item"></param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                internal string CheckboxItem(int index, string target, string suffix, SetItem item, IDictionary attributes)
                {
                        if (item.IsSelected)
                        {
                                AddChecked(attributes);
                        }
                        else
                        {
                                RemoveChecked(attributes);
                        }

                        target = String.Format("{0}[{1}]", target, index);
                        
                        string elementId = CreateHtmlId(attributes, target, true);
                        
                        string computedTarget = target;
                        
                        if (suffix != null && suffix != String.Empty)
                        {
                                computedTarget += "." + suffix;
                        }

                        return CreateInputElement("checkbox", elementId, computedTarget, item.Value, attributes);
                }

                /// <summary>
                /// Creates a label for an item of the checkbox list (internal use). The method mirrors
                /// <see cref="CheckboxItem"/> to ensure that the HTML ID is created consistently.
                /// </summary>
                /// <param name="index">Index for creating HTML ID</param>
                /// <param name="target">Target object for which the HTML ID is needed</param>
                /// <param name="suffix"></param>
                /// <param name="label">The label to display</param>
                /// <param name="attributes">additional attributes that influence HTML ID creation</param>
                /// <returns></returns>
                internal string CheckboxLabel(int index, string target, string suffix, string label, IDictionary attributes)
                {
                        target = String.Format("{0}[{1}]", target, index);

                        string elementId = CreateHtmlId(attributes, target, true);

                        return "<label for=\"" + elementId + "\" " + GetAttributes(attributes) + ">" + label + "</label>";
                }

                /// <summary>
                /// This class is an enumerable list of checkboxes. 
                /// It uses the <see cref="OperationState"/> to manage the sets
                /// and to control the check/uncheck state.
                /// </summary>
                public sealed class CheckboxList : IEnumerable, IEnumerator
                {
                        private readonly FormHelper helper;
                        private readonly string target;
                        private readonly IDictionary attributes;
                        private readonly OperationState operationState;
                        private readonly IEnumerator enumerator;
                        private bool hasMovedNext, hasItem;
                        private int index = -1;

                        /// <summary>
                        /// Initializes a new instance of the <see cref="CheckboxList"/> class.
                        /// </summary>
                        /// <param name="helper">The helper.</param>
                        /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                        /// <param name="initialSelectionSet">The initial selection set.</param>
                        /// <param name="dataSource">The set of available elements</param>
                        /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                        public CheckboxList(FormHelper helper, string target,
                                                                object initialSelectionSet, IEnumerable dataSource, IDictionary attributes)
                        {
                                if (dataSource == null) throw new ArgumentNullException("dataSource");

                                this.helper = helper;
                                this.target = target;
                                this.attributes = attributes ?? new HybridDictionary(true);
                                
                                operationState = SetOperation.IterateOnDataSource(initialSelectionSet, dataSource, attributes);
                                enumerator = operationState.GetEnumerator();
                        }
                        
                        /// <summary>
                        /// Outputs the Checkbox in the correct state (checked/unchecked) based
                        /// on the Set. 
                        /// <seealso cref="FormHelper.CreateCheckboxList(string,IEnumerable,IDictionary)"/>
                        /// </summary>
                        /// <returns>The generated input element</returns>
                        public string Item()
                        {
                                return Item(null);
                        }

                        /// <summary>
                        /// Outputs the Checkbox in the correct state (checked/unchecked) based
                        /// on the Set. 
                        /// <seealso cref="FormHelper.CreateCheckboxList(string,IEnumerable,IDictionary)"/>
                        /// </summary>
                        /// <param name="id">The element id</param>
                        /// <returns>The generated input element</returns>
                        public string Item(string id)
                        {
                                if (!hasMovedNext)
                                {
                                        throw new InvalidOperationException("Before rendering a checkbox item, you must use MoveNext");
                                }

                                if (!hasItem)
                                {
                                        // Nothing to render
                                        return String.Empty;
                                }

                                if (id != null)
                                {
                                        attributes["id"] = id;
                                }

                                return helper.CheckboxItem(index, target, operationState.TargetSuffix, CurrentSetItem, attributes);
                        }

                        /// <summary>
                        /// Outputs a label for the current checkbox element based on the generated id. 
                        /// <seealso cref="FormHelper.CreateCheckboxList(string,IEnumerable,IDictionary)"/>
                        /// </summary>
                        /// <param name="label">The text to display</param>
                        /// <returns>The generated label element</returns>
                        public string LabelFor(string label)
                        {
                                return LabelFor(null, label, null);
                        }

                        /// <summary>
                        /// Outputs a label for the current checkbox element based on the generated id.
                        /// <seealso cref="FormHelper.CreateCheckboxList(string,IEnumerable,IDictionary)"/>
                        /// </summary>
                        /// <param name="label">The text to display</param>
                        /// <param name="attributes">The attributes.</param>
                        /// <returns>The generated label element</returns>
                        public string LabelFor(string label, IDictionary attributes)
                        {
                                return LabelFor(null, label, attributes);
                        }

                        /// <summary>
                        /// Outputs a label for the current checkbox element based on the given id.
                        /// <seealso cref="FormHelper.CreateCheckboxList(string,IEnumerable,IDictionary)"/>
                        /// </summary>
                        /// <param name="id">The id to use within the label</param>
                        /// <param name="label">The text to display</param>
                        /// <param name="attributes">The attributes.</param>
                        /// <returns>The generated label element</returns>
                        public string LabelFor(string id, string label, IDictionary attributes)
                        {
                                if (!hasMovedNext)
                                {
                                        throw new InvalidOperationException("Before rendering a checkbox item, you must use MoveNext");
                                }

                                if (attributes == null)
                                {
                                        attributes = new HybridDictionary(true);
                                }

                                if (!hasItem)
                                {
                                        // Nothing to render
                                        return String.Empty;
                                }

                                if (id != null)
                                {
                                        attributes["id"] = id;
                                }

                                return helper.CheckboxLabel(index, target, operationState.TargetSuffix, label, attributes);
                        }

                        /// <summary>
                        /// Returns an enumerator that iterates through a collection.
                        /// </summary>
                        /// <returns>
                        /// An <see cref="T:System.Collections.IEnumerator"></see> object that can be used to iterate through the collection.
                        /// </returns>
                        public IEnumerator GetEnumerator()
                        {
                                return this;
                        }

                        /// <summary>
                        /// Advances the enumerator to the next element of the collection.
                        /// </summary>
                        /// <returns>
                        /// true if the enumerator was successfully advanced to the next element; false if the enumerator has passed the end of the collection.
                        /// </returns>
                        /// <exception cref="T:System.InvalidOperationException">The collection was modified after the enumerator was created. </exception>
                        public bool MoveNext()
                        {
                                hasMovedNext = true;
                                hasItem = enumerator.MoveNext();
                                
                                if (hasItem) index++;
                                
                                return hasItem;
                        }

                        /// <summary>
                        /// Sets the enumerator to its initial position, which is before the first element in the collection.
                        /// </summary>
                        /// <exception cref="T:System.InvalidOperationException">The collection was modified after the enumerator was created. </exception>
                        public void Reset()
                        {
                                index = -1;
                                enumerator.Reset();
                        }

                        /// <summary>
                        /// Gets the current element in the collection.
                        /// </summary>
                        /// <value></value>
                        /// <returns>The current element in the collection.</returns>
                        /// <exception cref="T:System.InvalidOperationException">The enumerator is positioned before the first element of the collection or after the last element. </exception>
                        public object Current
                        {
                                get { return CurrentSetItem.Item; }
                        }

                        /// <summary>
                        /// Gets the current set item.
                        /// </summary>
                        /// <value>The current set item.</value>
                        public SetItem CurrentSetItem
                        {
                                get { return enumerator.Current as SetItem; }
                        }
                }

                #endregion
                
                #region CheckboxField

                /// <summary>
                /// Generates a checkbox field. In fact it generates two as a
                /// way to send a value if the primary checkbox is not checked.
                /// This allow the process the be aware of the unchecked value
                /// and act accordingly.
                /// </summary>
                /// 
                /// <example>
                /// Consider the following view code:
                /// 
                /// <code lang="none">
                /// $Form.CheckboxField('user.disabled')
                /// </code>
                /// 
                /// That is going to output:
                /// 
                /// <code lang="none">
                ///  &lt;input type=&quot;checkbox&quot; id=&quot;user_disabled&quot; name=&quot;user.disabled&quot; value=&quot;true&quot; /&gt;
                ///  &lt;input type=&quot;hidden&quot; id=&quot;user_disabledH&quot; name=&quot;user.disabled&quot; value=&quot;false&quot; /&gt; 
                /// </code>
                /// 
                /// </example>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <returns>The generated form element</returns>
                public virtual string CheckboxField(string target)
                {
                        return CheckboxField(target, null);
                }

                /// <summary>
                /// Generates a checkbox field. In fact it generates two as a
                /// way to send a value if the primary checkbox is not checked.
                /// This allow the process the be aware of the unchecked value
                /// and act accordingly.
                /// 
                /// <para>
                /// The checked and unchecked values sent to the server defaults
                /// to true and false. You can override them using the 
                /// parameters <c>trueValue</c> and <c>falseValue</c>, but the DataBinder is prepared only
                /// to treat boolean arrays. 
                /// </para>
                /// 
                /// </summary>
                /// 
                /// <seealso cref="CheckboxField(string)"/>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string CheckboxField(string target, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        object value = ObtainValue(target);

                        string trueValue = CommonUtils.ObtainEntryAndRemove(attributes, "trueValue", "true");
                        
                        bool isChecked;

                        if (trueValue != "true")
                        {
                                isChecked = AreEqual(value, trueValue);
                        }
                        else
                        {
                                isChecked = ((value != null && value is bool && ((bool)value)) || 
                                                         (!(value is bool) && (value != null) && 
                                                         (!(value is string) || ((string) value).ToLower() != "false")));
                        }

                        if (isChecked)
                        {
                                if (attributes == null)
                                {
                                        attributes = new HybridDictionary(true);
                                }

                                AddChecked(attributes);
                        }

                        ApplyValidation(InputElementType.Checkbox, target, ref attributes);

                        string id = CreateHtmlId(attributes, target);
                        string hiddenElementId = id + "H";
                        string hiddenElementValue = CommonUtils.ObtainEntryAndRemove(attributes, "falseValue", "false");

                        string result = CreateInputElement("checkbox", id, target, trueValue, attributes);
                        
                        result += CreateInputElement("hidden", hiddenElementId, target, hiddenElementValue, null);
                        
                        return result;
                }

                #endregion

                #region RadioField

                /// <summary>
                /// Generates a radio input type with the specified 
                /// value to send to the served in case the element in checked.
                /// It will automatically check the radio if the target 
                /// evaluated value is equal to the specified <c>valueToSend</c>.
                /// </summary>
                /// 
                /// <example>
                ///     Consider the following action code:
                /// 
                /// <code>
                /// public void Index()
                /// {
                ///             PropertyBag["mode"] = FileMode.Truncate;
                /// }
                /// </code>
                /// 
                /// And the following view code:
                /// 
                /// <code lang="none">
                ///   $Form.RadioField("mode", "Append") FileMode.Append 
                ///   $Form.RadioField("mode", "Create") FileMode.Create 
                ///   $Form.RadioField("mode", "CreateNew") FileMode.CreateNew 
                ///   $Form.RadioField("mode", "Open") FileMode.Open 
                ///   $Form.RadioField("mode", "OpenOrCreate", "%{id='customhtmlid'}") FileMode.OpenOrCreate 
                ///   $Form.RadioField("mode", "Truncate") FileMode.Truncate 
                /// </code>
                /// 
                /// That is going to output:
                /// 
                /// <code lang="none">
                ///  &lt;input type=&quot;radio&quot; id=&quot;mode&quot; name=&quot;mode&quot; value=&quot;Append&quot; /&gt; FileMode.Append 
                ///  &lt;input type=&quot;radio&quot; id=&quot;mode&quot; name=&quot;mode&quot; value=&quot;Create&quot; /&gt; FileMode.Create 
                ///  &lt;input type=&quot;radio&quot; id=&quot;mode&quot; name=&quot;mode&quot; value=&quot;CreateNew&quot; /&gt; FileMode.CreateNew  
                ///  &lt;input type=&quot;radio&quot; id=&quot;mode&quot; name=&quot;mode&quot; value=&quot;Open&quot; /&gt; FileMode.Open 
                ///  &lt;input type=&quot;radio&quot; id=&quot;customhtmlid&quot; name=&quot;mode&quot; value=&quot;OpenOrCreate&quot; /&gt; FileMode.OpenOrCreate  
                ///  &lt;input type=&quot;radio&quot; id=&quot;mode&quot; name=&quot;mode&quot; value=&quot;Truncate&quot; checked=&quot;checked&quot; /&gt; FileMode.Truncate 
                /// </code>
                /// 
                /// </example>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="valueToSend"></param>
                /// <returns>The generated form element</returns>
                public virtual string RadioField(string target, object valueToSend)
                {
                        return RadioField(target, valueToSend, null);
                }

                /// <summary>
                /// Generates a radio input type with the specified 
                /// value to send to the served in case the element in checked.
                /// It will automatically check the radio if the target 
                /// evaluated value is equal to the specified <c>valueToSend</c>.
                /// </summary>
                /// 
                /// <seealso cref="RadioField(string,object)"/>
                /// 
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="valueToSend"></param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string RadioField(string target, object valueToSend, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        object value = ObtainValue(target);

                        bool isChecked = AreEqual(valueToSend, value);

                        if (isChecked)
                        {
                                if (attributes == null)
                                {
                                        attributes = new HybridDictionary(true);
                                }

                                AddChecked(attributes);
                        }

                        return CreateInputElement("radio", target, valueToSend, attributes);
                }

                #endregion

                #region FileField

                /// <summary>
                /// Generates an input file element.
                /// <para>
                /// Dirrently than other operations exposed by this helper, 
                /// no value is extracted for this operation
                /// </para>
                /// </summary>
                /// <param name="target">The object to be based on when creating the element name.</param>
                /// <returns>The generated form element</returns>
                public virtual string FileField(string target)
                {
                        return FileField(target, null);
                }

                /// <summary>
                /// Generates an input file element.
                /// <para>
                /// Dirrently than other operations exposed by this helper, 
                /// no value is extracted for this operation
                /// </para>
                /// </summary>
                /// <param name="target">The object to be based on when creating the element name.</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string FileField(string target, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        ApplyValidation(InputElementType.Text, target, ref attributes);

                        return CreateInputElement("file", target, string.Empty, attributes);
                }

                #endregion

                #region Select

                /// <summary>
                /// Creates a <c>select</c> element and its <c>option</c>s based on the <c>dataSource</c>.
                /// If the <c>dataSource</c>
                /// elements are complex objects (ie not string or primitives), 
                /// supply the parameters <c>value</c> and <c>text</c> to the dictionary to make
                /// the helper use the specified properties to extract the <c>option</c> value and content respectively.
                /// <para>
                /// You can also specify the attribute <c>firstoption</c> to force the first option be
                /// something like 'please select'. You can set the value of <c>firstoption</c> by specifying the attribute
                /// <c>firstoptionvalue</c>. The default value is '0'.
                /// </para>
                /// <para>
                /// Usually the <c>target</c> is a single value and the <c>dataSource</c> is obviously 
                /// a set with multiple items. The element types tend to be the same. If 
                /// they are not, you might have to specify the <c>suffix</c> parameters on 
                /// the <c>attributes</c> as it would not be inferred.
                /// </para>
                /// <para>
                /// The target can also be a set. In this case the intersection will be 
                /// the initially selected elements.
                /// </para>
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="dataSource">The set of available elements</param>
                /// <returns>The generated form element</returns>
                public virtual string Select(string target, IEnumerable dataSource)
                {
                        return Select(target, dataSource, null);
                }

                /// <summary>
                /// Creates a <c>select</c> element and its <c>option</c>s based on the <c>dataSource</c>.
                /// If the <c>dataSource</c>
                /// elements are complex objects (ie not string or primitives), 
                /// supply the parameters <c>value</c> and <c>text</c> to the dictionary to make
                /// the helper use the specified properties to extract the <c>option</c> value and content respectively.
                /// <para>
                /// You can also specify the attribute <c>firstoption</c> to force the first option be
                /// something like 'please select'. You can set the value of <c>firstoption</c> by specifying the attribute
                /// <c>firstoptionvalue</c>. The default value is '0'.
                /// </para>
                /// <para>
                /// Usually the <c>target</c> is a single value and the <c>dataSource</c> is obviously 
                /// a set with multiple items. The element types tend to be the same. If 
                /// they are not, you might have to specify the <c>suffix</c> parameters on 
                /// the <c>attributes</c> as it would not be inferred.
                /// </para>
                /// <para>
                /// The target can also be a set. In this case the intersection will be 
                /// the initially selected elements.
                /// </para>
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="dataSource">The set of available elements</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string Select(string target, IEnumerable dataSource, IDictionary attributes)
                {
                        target = RewriteTargetIfWithinObjectScope(target);

                        object selectedValue = ObtainValue(target);

                        return Select(target, selectedValue, dataSource, attributes);
                }
                
                /// <summary>
                /// Creates a <c>select</c> element and its <c>option</c>s based on the <c>dataSource</c>.
                /// If the <c>dataSource</c>
                /// elements are complex objects (ie not string or primitives), 
                /// supply the parameters <c>value</c> and <c>text</c> to the dictionary to make
                /// the helper use the specified properties to extract the <c>option</c> value and content respectively.
                /// <para>
                /// You can also specify the attribute <c>firstoption</c> to force the first option be
                /// something like 'please select'. You can set the value of <c>firstoption</c> by specifying the attribute
                /// <c>firstoptionvalue</c>. The default value is '0'.
                /// </para>
                /// <para>
                /// Usually the <c>target</c> is a single value and the <c>dataSource</c> is obviously 
                /// a set with multiple items. The element types tend to be the same. If 
                /// they are not, you might have to specify the <c>suffix</c> parameters on 
                /// the <c>attributes</c> as it would not be inferred.
                /// </para>
                /// <para>
                /// The target can also be a set. In this case the intersection will be 
                /// the initially selected elements.
                /// </para>
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="selectedValue"></param>
                /// <param name="dataSource">The set of available elements</param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                public virtual string Select(string target, object selectedValue, IEnumerable dataSource, IDictionary attributes)
                {
                        return GenerateSelect(target, selectedValue, dataSource, attributes);
                }

                /// <summary>
                /// Generates the select.
                /// </summary>
                /// <param name="target">The target.</param>
                /// <param name="selectedValue">The selected value.</param>
                /// <param name="dataSource">The data source.</param>
                /// <param name="attributes">The attributes.</param>
                /// <returns></returns>
                protected virtual string GenerateSelect(string target, object selectedValue, IEnumerable dataSource, IDictionary attributes)
                {
                        string id = CreateHtmlId(target);

                        ApplyValidation(InputElementType.Select, target, ref attributes);

                        StringBuilder sb = new StringBuilder();
                        StringWriter sbWriter = new StringWriter(sb);
                        HtmlTextWriter writer = new HtmlTextWriter(sbWriter);

                        string firstOption = null;
                        string firstOptionValue = null;
                        string name = target;

                        if (attributes != null)
                        {
                                firstOption = CommonUtils.ObtainEntryAndRemove(attributes, "firstoption");
                                firstOptionValue = CommonUtils.ObtainEntryAndRemove(attributes, "firstoptionvalue");

                                if (attributes.Contains("name"))
                                {
                                        name = (String) attributes["name"];
                                        attributes.Remove("name");
                                }

                                if (attributes.Contains("id"))
                                {
                                        id = (String) attributes["id"];
                                        attributes.Remove("id");
                                }
                        }

                        OperationState state = SetOperation.IterateOnDataSource(selectedValue, dataSource, attributes);

                        writer.WriteBeginTag("select");
                        writer.WriteAttribute("id", id);
                        writer.WriteAttribute("name", name);
                        writer.Write(" ");
                        writer.Write(GetAttributes(attributes));
                        writer.Write(HtmlTextWriter.TagRightChar);
                        writer.WriteLine();

                        if (firstOption != null)
                        {
                                writer.WriteBeginTag("option");
                                writer.WriteAttribute("value", (firstOptionValue == null) ? "0" : SafeHtmlEncode(firstOptionValue));
                                writer.Write(HtmlTextWriter.TagRightChar);
                                writer.Write(SafeHtmlEncode(firstOption));
                                writer.WriteEndTag("option");
                                writer.WriteLine();
                        }

                        foreach(SetItem item in state)
                        {
                                writer.WriteBeginTag("option");

                                if (item.IsSelected)
                                {
                                        writer.Write(" selected=\"selected\"");
                                }

                                writer.WriteAttribute("value", SafeHtmlEncode(item.Value));
                                writer.Write(HtmlTextWriter.TagRightChar);
                                writer.Write(SafeHtmlEncode(item.Text));
                                writer.WriteEndTag("option");
                                writer.WriteLine();
                        }

                        writer.WriteEndTag("select");

                        return sbWriter.ToString();
                }

                #endregion

                #region Field set

                /// <summary>
                /// Creates a field set element with a legend using the specified name.
                /// </summary>
                /// <param name="name">The name.</param>
                /// <returns></returns>
                public virtual string FieldSet(string name)
                {
                        return "<fieldset><legend>" + name + "</legend>";
                }

                /// <summary>
                /// Creates an element to close a fieldset element.
                /// </summary>
                /// <returns></returns>
                public virtual string EndFieldSet()
                {
                        return "</fieldset>";
                }

                #endregion

                #region Enum

                /// <summary>
                /// Creates a list of pairs for the enum type. 
                /// </summary>
                /// <param name="enumType">enum type.</param>
                /// <returns></returns>
                public static Pair<int, string>[] EnumToPairs(Type enumType)
                {
                        if (enumType == null) throw new ArgumentNullException("enumType");
                        if (!enumType.IsEnum) throw new ArgumentException("enumType must be an Enum", "enumType");

                        Array values = Enum.GetValues(enumType);
                        string[] names = Enum.GetNames(enumType);

                        List<Pair<int, string>> listOfPairs = new List<Pair<int, string>>();
                        int index = 0;

                        foreach(string name in names)
                        {
                                int value = Convert.ToInt32(values.GetValue(index++));
                                listOfPairs.Add(new Pair<int, string>(value, TextHelper.PascalCaseToWord(name)));
                        }

                        return listOfPairs.ToArray();
                }

                #endregion 

                #region Validation

                /// <summary>
                /// Configures this FormHelper instance to use the supplied
                /// web validator to generate field validation.
                /// </summary>
                /// <param name="provider">The validation provider.</param>
                public virtual void UseWebValidatorProvider(IBrowserValidatorProvider provider)
                {
                        if (provider == null) throw new ArgumentNullException("provider");

                        validatorProvider = provider;
                }

                /// <summary>
                /// Configures this FormHelper instance to use Prototype for form fields validation
                /// </summary>
                public virtual void UsePrototypeValidation()
                {
                        UseWebValidatorProvider(new PrototypeWebValidator());
                }

                /// <summary>
                /// Configures this FormHelper instance to use fValidate for form fields validation
                /// </summary>
                public virtual void UsefValidate()
                {
                        UseWebValidatorProvider(new FValidateWebValidator());
                }

                /// <summary>
                /// Configures this FormHelper instance to use Zebda for form fields validation
                /// </summary>
                public virtual void UseZebdaValidation()
                {
                        UseWebValidatorProvider(new ZebdaWebValidator());
                }

                /// <summary>
                /// Disables the validation.
                /// </summary>
                public virtual void DisableValidation()
                {
                        isValidationDisabled = true;
                }

                /// <summary>
                /// Applies the validation.
                /// </summary>
                /// <param name="inputType">Type of the input.</param>
                /// <param name="target">The target.</param>
                /// <param name="attributes">The attributes.</param>
                protected virtual void ApplyValidation(InputElementType inputType, string target, ref IDictionary attributes)
                {
                        bool disableValidation = CommonUtils.ObtainEntryAndRemove(attributes, "disablevalidation", "false") == "true";

                        if (!IsValidationEnabled || disableValidation)
                        {
                                return;
                        }

                        if (validatorRegistry == null || validationConfig == null)
                        {
                                return;
                        }

                        if (attributes == null)
                        {
                                attributes = new HybridDictionary(true);
                        }

                        IValidator[] validators = CollectValidators(RequestContext.All, target);

                        IBrowserValidationGenerator generator = validatorProvider.CreateGenerator(validationConfig, inputType, attributes);

                        foreach(IValidator validator in validators)
                        {
                                if (validator.SupportsBrowserValidation)
                                {
                                        validator.ApplyBrowserValidation(validationConfig, inputType, generator, attributes, target);
                                }
                        }
                }

                private IValidator[] CollectValidators(RequestContext requestContext, string target)
                {
                        List<IValidator> validators = new List<IValidator>();

                        ObtainTargetProperty(requestContext, target, delegate(PropertyInfo property)
                        {
                                validators.AddRange(validatorRegistry.GetValidators(ValidatorRunner, property.DeclaringType, property, RunWhen.Everytime));
                        });

                        return validators.ToArray();
                }

                private bool IsValidationEnabled
                {
                        get
                        {
                                if (isValidationDisabled) return false;

                                if (objectStack.Count == 0) return true;

                                return ((FormScopeInfo)objectStack.Peek()).IsValidationEnabled;
                        }
                }

                #endregion

                #region protected members

                /// <summary>
                /// Rewrites the target if within object scope.
                /// </summary>
                /// <param name="target">The target.</param>
                /// <returns></returns>
                protected string RewriteTargetIfWithinObjectScope(string target)
                {
                        if (objectStack.Count == 0)
                        {
                                return target;
                        }
                        else
                        {
                                return ((FormScopeInfo) objectStack.Peek()).RootTarget + "." + target;
                        }
                }

                /// <summary>
                /// Creates the specified input element 
                /// using the specified parameters to supply the name, value, id and others 
                /// html attributes.
                /// </summary>
                /// <param name="type"></param>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="value"></param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                protected virtual string CreateInputElement(string type, string target, Object value, IDictionary attributes)
                {
                        if (value == null)
                        {
                                value = CommonUtils.ObtainEntryAndRemove(attributes, "defaultValue");
                        }

                        string id = CreateHtmlId(attributes, target);

                        return CreateInputElement(type, id, target, FormatIfNecessary(value, attributes), attributes);
                }

                /// <summary>
                /// Creates the specified input element 
                /// using the specified parameters to supply the name, value, id and others 
                /// html attributes.
                /// </summary>
                /// <param name="type"></param>
                /// <param name="id"></param>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <param name="value"></param>
                /// <param name="attributes">Attributes for the FormHelper method and for the html element it generates</param>
                /// <returns>The generated form element</returns>
                protected virtual string CreateInputElement(string type, string id, string target, string value, IDictionary attributes)
                {
                        value = FormatIfNecessary(value, attributes);

                        value = SafeHtmlEncode(value);

                        if (attributes != null && attributes.Contains("mask"))
                        {
                                string mask = CommonUtils.ObtainEntryAndRemove(attributes, "mask");
                                string maskSep = CommonUtils.ObtainEntryAndRemove(attributes, "mask_separator", "-");

                                string onBlur = CommonUtils.ObtainEntryAndRemove(attributes, "onBlur", "void(0)");
                                string onKeyUp = CommonUtils.ObtainEntryAndRemove(attributes, "onKeyUp", "void(0)");

                                string js = "return monorail_formhelper_mask(event,this,'" + mask + "','" + maskSep + "');";

                                attributes["onBlur"] = "javascript:" + onBlur + ";" + js;
                                attributes["onKeyUp"] = "javascript:" + onKeyUp + ";" + js;
                        }
                        
                        return String.Format("<input type=\"{0}\" id=\"{1}\" name=\"{2}\" value=\"{3}\" {4}/>", 
                                                                 type, id, target, value, GetAttributes(attributes));
                }

                /// <summary>
                /// Creates the input element.
                /// </summary>
                /// <param name="type">The type.</param>
                /// <param name="value">The value.</param>
                /// <param name="attributes">The attributes.</param>
                /// <returns></returns>
                protected virtual string CreateInputElement(string type, string value, IDictionary attributes)
                {
                        return String.Format("<input type=\"{0}\" value=\"{1}\" {2}/>",
                                                                 type, FormatIfNecessary(value, attributes), GetAttributes(attributes));
                }

                /// <summary>
                /// Formats if necessary.
                /// </summary>
                /// <param name="value">The value.</param>
                /// <param name="attributes">The attributes.</param>
                /// <returns></returns>
                protected static string FormatIfNecessary(object value, IDictionary attributes)
                {
                        string formatString = CommonUtils.ObtainEntryAndRemove(attributes, "textformat");

                        if (value != null && formatString != null)
                        {
                                IFormattable formattable = value as IFormattable;

                                if (formattable != null)
                                {
                                        value = formattable.ToString(formatString, null);
                                }
                        }
                        else if (value == null)
                        {
                                value = String.Empty;
                        }

                        return value.ToString();
                }

                /// <summary>
                /// Obtains the target property.
                /// </summary>
                /// <param name="context">The context.</param>
                /// <param name="target">The target.</param>
                /// <param name="action">The action.</param>
                /// <returns></returns>
                protected PropertyInfo ObtainTargetProperty(RequestContext context, string target, Action<PropertyInfo> action)
                {
                        string[] pieces;

                        Type root = ObtainRootType(context, target, out pieces);

                        if (root != null && pieces.Length > 1)
                        {
                                return QueryPropertyInfoRecursive(root, pieces, 1, action);
                        }

                        return null;
                }

                /// <summary>
                /// Queries the context for the target value
                /// </summary>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <returns>The generated form element</returns>
                protected object ObtainValue(string target)
                {
                        return ObtainValue(RequestContext.All, target);
                }

                /// <summary>
                /// Queries the context for the target value
                /// </summary>
                /// <param name="context"></param>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <returns>The generated form element</returns>
                protected object ObtainValue(RequestContext context, string target)
                {
                        string[] pieces;

                        object rootInstance = ObtainRootInstance(context, target, out pieces);

                        if (rootInstance != null && pieces.Length > 1)
                        {
                                return QueryPropertyRecursive(rootInstance, pieces, 1);
                        }

                        return rootInstance;
                }

                /// <summary>
                /// Obtains the root instance.
                /// </summary>
                /// <param name="context">The context.</param>
                /// <param name="target">The object to get the value from and to be based on to create the element name.</param>
                /// <returns>The generated form element</returns>
                protected object ObtainRootInstance(RequestContext context, string target)
                {
                        object rootInstance = null;

                        if (context == RequestContext.All || context == RequestContext.PropertyBag)
                        {
                                rootInstance = ControllerContext.PropertyBag[target];
                        }
                        if (rootInstance == null && (context == RequestContext.All || context == RequestContext.Flash))
                        {
                                rootInstance = Context.Flash[target];
                        }
                        if (rootInstance == null && (context == RequestContext.All || context == RequestContext.Session))
                        {
                                rootInstance = Context.Session[target];
                        }
                        if (rootInstance == null && (context == RequestContext.All || context == RequestContext.Params))
                        {
                                rootInstance = Context.Request.Params[target];
                        }
                        if (rootInstance == null && (context == RequestContext.All || context == RequestContext.Request))
                        {
                                rootInstance = Context.Items[target];
                        }

                        return rootInstance;
                }

                /// <summary>
                /// Obtains the root instance.
                /// </summary>
                /// <param name="context">The context.</param>
                /// <param name="target">The target.</param>
                /// <param name="pieces">The pieces.</param>
                /// <returns></returns>
                protected object ObtainRootInstance(RequestContext context, string target, out string[] pieces)
                {
                        pieces = target.Split(new char[] {'.'});

                        string root = pieces[0];

                        int index;

                        bool isIndexed = CheckForExistenceAndExtractIndex(ref root, out index);

                        object rootInstance = ObtainRootInstance(context, root);

                        if (rootInstance == null)
                        {
                                return null;
                        }

                        if (isIndexed)
                        {
                                AssertIsValidArray(rootInstance, root, index);
                        }
        
                        if (!isIndexed && pieces.Length == 1)
                        {
                                return rootInstance;
                        }
                        else if (isIndexed)
                        {
                                rootInstance = GetArrayElement(rootInstance, index);
                        }

                        return rootInstance;
                }

                /// <summary>
                /// Obtains the type of the root.
                /// </summary>
                /// <param name="context">The context.</param>
                /// <param name="target">The target.</param>
                /// <param name="pieces">The pieces.</param>
                /// <returns></returns>
                private Type ObtainRootType(RequestContext context, string target, out string[] pieces)
                {
                        pieces = target.Split(new char[] { '.' });

                        Type foundType = (Type) ControllerContext.PropertyBag[pieces[0] + "type"];

                        if (foundType == null)
                        {
                            string trimmed = pieces[0].Split('[')[0];

                                foundType = (Type) ControllerContext.PropertyBag[trimmed + "type"];

                                if (foundType == null)
                                {
                                        object root = ObtainRootInstance(context, target, out pieces);

                                        if (root != null)
                                        {
                                                foundType = root.GetType();
                                        }
                                }
                        }

                        return foundType;
                }

                private static PropertyInfo QueryPropertyInfoRecursive(Type type, string[] propertyPath)
                {
                        return QueryPropertyInfoRecursive(type, propertyPath, 0, null);
                }

                private static PropertyInfo QueryPropertyInfoRecursive(Type type, string[] propertyPath, int piece, Action<PropertyInfo> action)
                {
                        string property = propertyPath[piece]; int index;

                        bool isIndexed = CheckForExistenceAndExtractIndex(ref property, out index);

                        PropertyInfo propertyInfo = type.GetProperty(property, ResolveFlagsToUse(type));

                        if (propertyInfo == null)
                        {
                                if (logger.IsErrorEnabled)
                                {
                                        logger.Error("No public property '{0}' found on type '{1}'", property, type.FullName);
                                }

                                return null;
                        }

                        if (!propertyInfo.CanRead)
                        {
                                throw new BindingException("Property '{0}' for type '{1}' can not be read",
                                        propertyInfo.Name, type.FullName);
                        }

                        if (propertyInfo.GetIndexParameters().Length != 0)
                        {
                                throw new BindingException("Property '{0}' for type '{1}' has indexes, which are not supported",
                                        propertyInfo.Name, type.FullName);
                        }

                        if (action != null)
                        {
                                action(propertyInfo);
                        }

                        type = propertyInfo.PropertyType;

                        if (typeof(ICollection).IsAssignableFrom(type))
                        {
                                return null;
                        }

                        if (isIndexed)
                        {
                                if (type.IsGenericType)
                                {
                                        Type[] args = type.GetGenericArguments();
                                        if (args.Length != 1)
                                                throw new BindingException("Expected the generic indexed property '{0}' to be of 1 element", type.Name);
                                        type = args[0];
                                }

                                if (type.IsArray)
                                {
                                        type = type.GetElementType();
                                }
                        }

                        if (piece + 1 == propertyPath.Length)
                        {
                                return propertyInfo;
                        }

                        return QueryPropertyInfoRecursive(type, propertyPath, piece + 1, action);
                }

                /// <summary>
                /// Query property paths agains the rootInstance type
                /// </summary>
                /// <param name="rootInstance">the object to query</param>
                /// <param name="propertyPath">property path</param>
                /// <returns>The generated form element</returns>
                protected static object QueryPropertyRecursive(object rootInstance, string[] propertyPath)
                {
                        return QueryPropertyRecursive(rootInstance, propertyPath, 0);
                }

                /// <summary>
                /// Query property paths agains the rootInstance type
                /// </summary>
                /// <param name="rootInstance">the object to query</param>
                /// <param name="propertyPath">property path</param>
                /// <param name="piece">start index</param>
                /// <returns>The generated form element</returns>
                protected static object QueryPropertyRecursive(object rootInstance, string[] propertyPath, int piece)
                {
                        string property = propertyPath[piece]; int index;

                        Type instanceType = rootInstance.GetType();

                        bool isIndexed = CheckForExistenceAndExtractIndex(ref property, out index);

                        PropertyInfo propertyInfo = instanceType.GetProperty(property, ResolveFlagsToUse(instanceType));

                        object instance = null;

                        if (propertyInfo == null)
                        {
                                FieldInfo fieldInfo = instanceType.GetField(property, FieldFlags);

                                if (fieldInfo != null)
                                {
                                        instance = fieldInfo.GetValue(rootInstance);
                                }
                        }
                        else
                        {
                                if (!propertyInfo.CanRead)
                                {
                                        throw new BindingException("Property '{0}' for type '{1}' can not be read", 
                                                propertyInfo.Name, instanceType.FullName);
                                }
                                
                                if (propertyInfo.GetIndexParameters().Length != 0)
                                {
                                        throw new BindingException("Property '{0}' for type '{1}' has indexes, which are not supported", 
                                                propertyInfo.Name, instanceType.FullName);
                                }

                                instance = propertyInfo.GetValue(rootInstance, null);
                        }

                        if (isIndexed && instance != null)
                        {
                                AssertIsValidArray(instance, property, index);

                                instance = GetArrayElement(instance, index);
                        }

                        if (instance == null || piece + 1 == propertyPath.Length)
                        {
                                return instance;
                        }

                        return QueryPropertyRecursive(instance, propertyPath, piece + 1);
                }

                /// <summary>
                /// Creates the HTML id.
                /// </summary>
                /// <param name="attributes">The attributes.</param>
                /// <param name="target">The target.</param>
                /// <returns>The generated form element</returns>
                protected static string CreateHtmlId(IDictionary attributes, string target)
                {
                        return CreateHtmlId(attributes, target, true);
                }
                
                /// <summary>
                /// Creates the HTML id.
                /// </summary>
                /// <param name="attributes">The attributes.</param>
                /// <param name="target">The target.</param>
                /// <param name="removeEntry">if set to <c>true</c> [remove entry].</param>
                /// <returns>The generated form element</returns>
                protected static string CreateHtmlId(IDictionary attributes, string target, bool removeEntry)
                {
                        string id;
                        
                        if (removeEntry)
                        {
                                id = CommonUtils.ObtainEntryAndRemove(attributes, "id");
                        }
                        else
                        {
                                id = CommonUtils.ObtainEntry(attributes, "id");
                        }

                        if (id == null)
                        {
                                id = CreateHtmlId(target);
                        }
                        
                        return id;
                }

                #endregion

                #region private helpers

                private static void ApplyNumberOnlyOptions(IDictionary attributes)
                {
                        string list = CommonUtils.ObtainEntryAndRemove(attributes, "exceptions", String.Empty);
                        string forbid = CommonUtils.ObtainEntryAndRemove(attributes, "forbid", String.Empty);

                        attributes["onKeyPress"] = "return monorail_formhelper_numberonly(event, [" + list + "], [" + forbid + "]);";
                }

                private static void ApplyFilterOptions(IDictionary attributes)
                {
                        string forbid = CommonUtils.ObtainEntryAndRemove(attributes, "forbid", String.Empty);

                        attributes["onKeyPress"] = "return monorail_formhelper_inputfilter(event, [" + forbid + "]);";
                }

                private static void AssertIsValidArray(object instance, string property, int index)
                {
                        Type instanceType = instance.GetType();

                        IList list = instance as IList;

                        bool validList = false;

                        if (list == null && instanceType.IsGenericType)
                        {
                                Type[] genArgs = instanceType.GetGenericArguments();

                                Type genList = typeof(System.Collections.Generic.IList<>).MakeGenericType(genArgs);
                                Type genTypeDef = instanceType.GetGenericTypeDefinition().MakeGenericType(genArgs);

                                validList = genList.IsAssignableFrom(genTypeDef);
                        }
                        
                        if (!validList && list == null)
                        {
                                throw new MonoRailException("The property {0} is being accessed as " + 
                                        "an indexed property but does not seem to implement IList. " + 
                                        "In fact the type is {1}", property, instanceType.FullName);
                        }

                        if (index < 0)
                        {
                                throw new MonoRailException("The specified index '{0}' is outside the bounds " + 
                                        "of the array. Property {1}", index, property);
                        }
                }

                private static object GetArrayElement(object instance, int index)
                {
                        IList list = instance as IList;

                        if (list == null && instance != null && instance.GetType().IsGenericType)
                        {
                                Type instanceType = instance.GetType();

                                Type[] genArguments = instanceType.GetGenericArguments();

                                Type genType = instanceType.GetGenericTypeDefinition().MakeGenericType(genArguments);
                                
                                // I'm not going to retest for IList implementation as 
                                // if we got here, the AssertIsValidArray has run successfully

                                PropertyInfo countPropInfo = genType.GetProperty("Count");

                                int count = (int) countPropInfo.GetValue(instance, null);
                                
                                if (count == 0 || index + 1 > count)
                                {
                                        return null;
                                }

                                PropertyInfo indexerPropInfo = genType.GetProperty("Item");

                                return indexerPropInfo.GetValue(instance, new object[] { index });
                        }
                        
                        if (list == null || list.Count == 0 || index + 1 > list.Count)
                        {
                                return null;
                        }

                        return list[index];
                }

                private static bool CheckForExistenceAndExtractIndex(ref string property, out int index)
                {
                        bool isIndexed = property.IndexOf('[') != -1;

                        index = -1;

                        if (isIndexed)
                        {
                                int start = property.IndexOf('[') + 1;
                                int len = property.IndexOf(']', start) - start;

                                string indexStr = property.Substring(start, len);

                                try
                                {
                                        index = Convert.ToInt32(indexStr);
                                }
                                catch(Exception)
                                {
                                        throw new MonoRailException("Could not convert (param {0}) index to Int32. Value is {1}", 
                                                property, indexStr);
                                }

                                property = property.Substring(0, start - 1);
                        }

                        return isIndexed;
                }

                private static bool AreEqual(object left, object right)
                {
                        if (left == null || right == null) return false;

                        if (left is string && right is String)
                        {
                                return String.Compare(left.ToString(), right.ToString()) == 0;
                        }

                        if (left.GetType() == right.GetType())
                        {
                                return right.Equals(left);
                        }

                        IConvertible convertible = left as IConvertible;

                        if (convertible != null)
                        {
                                try
                                {
                                        object newleft = convertible.ToType(right.GetType(), null);
                                        return (newleft.Equals(right));
                                }
                                catch(Exception)
                                {
                                        // Do nothing
                                }
                        }

                        return left.ToString().Equals(right.ToString());
                }

                private string SafeHtmlEncode(string content)
                {
                        if (Context != null)
                        {
                                return HtmlEncode(content);
                        }

                        return content;
                }

                /// <summary>
                /// Determines whether the present value matches the value on 
                /// the initialSetValue (which can be a single value or a set)
                /// </summary>
                /// <param name="value">Value from the datasource</param>
                /// <param name="initialSetValue">Value from the initial selection set</param>
                /// <param name="propertyOnInitialSet">Optional. Property to obtain the value from</param>
                /// <param name="isMultiple"><c>true</c> if the initial selection is a set</param>
                /// <returns><c>true</c> if it's selected</returns>
                protected internal static bool IsPresent(object value, object initialSetValue, 
                                                                                                 ValueGetter propertyOnInitialSet, bool isMultiple)
                {
                        if (!isMultiple)
                        {
                                object valueToCompare = initialSetValue;
                                
                                if (propertyOnInitialSet != null)
                                {
                                        // propertyOnInitialSet.GetValue(initialSetValue, null);
                                        valueToCompare = propertyOnInitialSet.GetValue(initialSetValue); 
                                }
                                
                                return AreEqual(value, valueToCompare);
                        }
                        else
                        {
                                foreach(object item in (IEnumerable) initialSetValue)
                                {
                                        object valueToCompare = item;

                                        if (propertyOnInitialSet != null)
                                        {
                                                // valueToCompare = propertyOnInitialSet.GetValue(item, null);
                                                valueToCompare = propertyOnInitialSet.GetValue(item); 
                                        }

                                        if (AreEqual(value, valueToCompare))
                                        {
                                                return true;
                                        }
                                }
                        }
                        
                        return false;
                }
                
                private static void AddChecked(IDictionary attributes)
                {
                        attributes["checked"] = "checked";
                }

                private static void RemoveChecked(IDictionary attributes)
                {
                        attributes.Remove("checked");
                }

                private static string CreateHtmlId(string name)
                {
                        StringBuilder sb = new StringBuilder(name.Length);

                        bool canUseUnderline = false;

                        foreach(char c in name.ToCharArray())
                        {
                                switch(c)
                                {
                                        case '.':
                                        case '[':
                                        case ']':
                                                if (canUseUnderline)
                                                {
                                                        sb.Append('_');
                                                        canUseUnderline = false;
                                                }
                                                break;
                                        default:
                                                canUseUnderline = true;
                                                sb.Append(c);
                                                break;
                                }
                                
                        }

                        return sb.ToString();
                }

                /// <summary>
                /// Abstracts the approach to access values on objects. 
                /// </summary>
                public abstract class ValueGetter
                {
                        /// <summary>
                        /// Gets the name.
                        /// </summary>
                        /// <value>The name.</value>
                        public abstract string Name { get; }

                        /// <summary>
                        /// Gets the value.
                        /// </summary>
                        /// <param name="instance">The instance.</param>
                        /// <returns></returns>
                        public abstract object GetValue(object instance);
                }

                /// <summary>
                /// Implementation of <see cref="ValueGetter"/>
                /// that uses reflection to access values
                /// </summary>
                public class ReflectionValueGetter : ValueGetter
                {
                        private PropertyInfo propInfo;

                        /// <summary>
                        /// Initializes a new instance of the <see cref="ReflectionValueGetter"/> class.
                        /// </summary>
                        /// <param name="propInfo">The prop info.</param>
                        public ReflectionValueGetter(PropertyInfo propInfo)
                        {
                                this.propInfo = propInfo;
                        }

                        /// <summary>
                        /// Gets the name.
                        /// </summary>
                        /// <value>The name.</value>
                        public override string Name
                        {
                                get { return propInfo.Name; }
                        }

                        /// <summary>
                        /// Gets the value.
                        /// </summary>
                        /// <param name="instance">The instance.</param>
                        /// <returns></returns>
                        public override object GetValue(object instance)
                        {
                                try
                                {
                                        return propInfo.GetValue(instance, null);
                                }
                                catch(TargetException)
                                {
                                        PropertyInfo tempProp = instance.GetType().GetProperty(Name);

                                        if (tempProp == null)
                                        {
                                                throw;
                                        }

                                        return tempProp.GetValue(instance, null);
                                }
                        }
                }

                /// <summary>
                /// Implementation of <see cref="ValueGetter"/>
                /// that uses reflection and recusion to access values
                /// </summary>
                public class RecursiveReflectionValueGetter : ValueGetter
                {
                        private readonly string[] keyName;
                        private readonly string name = string.Empty;

                        /// <summary>
                        /// Initializes a new instance of the <see cref="RecursiveReflectionValueGetter"/> class.
                        /// </summary>
                        /// <param name="targetType">The target type to query</param>
                        /// <param name="keyName">the property path</param>
                        public RecursiveReflectionValueGetter(Type targetType, string keyName)
                        {
                                this.keyName = keyName.Split('.');
                                name = QueryPropertyInfoRecursive(targetType, this.keyName).Name;
                        }

                        /// <summary>
                        /// Gets the name.
                        /// </summary>
                        /// <value>The name.</value>
                        public override string Name
                        {
                                get { return name; }
                        }

                        /// <summary>
                        /// Gets the value.
                        /// </summary>
                        /// <param name="instance">The instance.</param>
                        /// <returns></returns>
                        public override object GetValue(object instance)
                        {
                                try
                                {
                                        return QueryPropertyRecursive(instance, keyName);
                                }
                                catch (TargetException)
                                {
                                        PropertyInfo tempProp = instance.GetType().GetProperty(Name);

                                        if (tempProp == null)
                                        {
                                                throw;
                                        }

                                        return tempProp.GetValue(instance, null);
                                }
                        }
                }

                /// <summary>
                /// Implementation of <see cref="ValueGetter"/>
                /// to access DataRow's value
                /// </summary>
                public class DataRowValueGetter : ValueGetter
                {
                        private readonly string columnName;

                        /// <summary>
                        /// Initializes a new instance of the <see cref="DataRowValueGetter"/> class.
                        /// </summary>
                        /// <param name="columnName">Name of the column.</param>
                        public DataRowValueGetter(string columnName)
                        {
                                this.columnName = columnName;
                        }

                        /// <summary>
                        /// Gets the name.
                        /// </summary>
                        /// <value>The name.</value>
                        public override string Name
                        {
                                get { return columnName; }
                        }

                        /// <summary>
                        /// Gets the value.
                        /// </summary>
                        /// <param name="instance">The instance.</param>
                        /// <returns></returns>
                        public override object GetValue(object instance)
                        {
                                DataRow row = (DataRow) instance;

                                return row[columnName];
                        }
                }

                /// <summary>
                /// Implementation of <see cref="ValueGetter"/>
                /// to access DataRowView's value
                /// </summary>
                public class DataRowViewValueGetter : ValueGetter
                {
                        private readonly string columnName;

                        /// <summary>
                        /// Initializes a new instance of the <see cref="DataRowViewValueGetter"/> class.
                        /// </summary>
                        /// <param name="columnName">Name of the column.</param>
                        public DataRowViewValueGetter(string columnName)
                        {
                                this.columnName = columnName;
                        }

                        /// <summary>
                        /// Gets the name.
                        /// </summary>
                        /// <value>The name.</value>
                        public override string Name
                        {
                                get { return columnName; }
                        }

                        /// <summary>
                        /// Gets the value.
                        /// </summary>
                        /// <param name="instance">The instance.</param>
                        /// <returns></returns>
                        public override object GetValue(object instance)
                        {
                                DataRowView row = (DataRowView)instance;

                                return row[columnName];
                        }
                }

                /// <summary>
                /// Empty implementation of a <see cref="ValueGetter"/>
                /// </summary>
                public class NoActionGetter : ValueGetter
                {
                        /// <summary>
                        /// Gets the name.
                        /// </summary>
                        /// <value>The name.</value>
                        public override string Name
                        {
                                get { return string.Empty; }
                        }

                        /// <summary>
                        /// Gets the value.
                        /// </summary>
                        /// <param name="instance">The instance.</param>
                        /// <returns></returns>
                        public override object GetValue(object instance)
                        {
                                return null;
                        }
                }

                /// <summary>
                /// Implementation of <see cref="ValueGetter"/>
                /// to access enum fields
                /// </summary>
                public class EnumValueGetter : ValueGetter
                {
                        private readonly Type enumType;

                        /// <summary>
                        /// Initializes a new instance of the <see cref="EnumValueGetter"/> class.
                        /// </summary>
                        /// <param name="enumType">Type of the enum.</param>
                        public EnumValueGetter(Type enumType)
                        {
                                this.enumType = enumType;
                        }

                        /// <summary>
                        /// Gets the name.
                        /// </summary>
                        /// <value>The name.</value>
                        public override string Name
                        {
                                get { return string.Empty; }
                        }

                        /// <summary>
                        /// Gets the value.
                        /// </summary>
                        /// <param name="instance">The instance.</param>
                        /// <returns></returns>
                        public override object GetValue(object instance)
                        {
                                return Convert.ToDecimal(Enum.Format(enumType, Enum.Parse(enumType, Convert.ToString(instance)), "d"));
                        }
                }

                /// <summary>
                /// Abstract factory for <see cref="ValueGetter"/> implementations
                /// </summary>
                public class ValueGetterAbstractFactory
                {
                        /// <summary>
                        /// Creates the specified target type.
                        /// </summary>
                        /// <param name="targetType">Type of the target.</param>
                        /// <param name="keyName">Name of the key.</param>
                        /// <returns></returns>
                        public static ValueGetter Create(Type targetType, string keyName)
                        {
                                if (targetType == null)
                                {
                                        return new NoActionGetter();
                                }
                                else if (targetType == typeof(DataRow))
                                {
                                        return new DataRowValueGetter(keyName);
                                }
                                else if (targetType == typeof(DataRowView))
                                {
                                        return new DataRowViewValueGetter(keyName);
                                }
                                else if (targetType.IsEnum)
                                {
                                        return new EnumValueGetter(targetType);
                                }
                                else
                                {
                                        PropertyInfo info;

                                        // check for recusion
                                        if(keyName.Contains("."))
                                        {
                                                info = QueryPropertyInfoRecursive(targetType, keyName.Split('.'));
                                                
                                                if (info != null)
                                                {
                                                        return new RecursiveReflectionValueGetter(targetType, keyName);
                                                }
                                        }
                                        else
                                        {
                                                info = targetType.GetProperty(keyName, ResolveFlagsToUse(targetType));
                                                if (info != null)
                                                {
                                                        return new ReflectionValueGetter(info);
                                                }
                                        }

                                        return null;
                                }
                        }
                }

                #endregion

                #region FormScopeInfo

                class FormScopeInfo
                {
                        private readonly string target;
                        private readonly bool isValidationEnabled;

                        /// <summary>
                        /// Initializes a new instance of the <see cref="FormScopeInfo"/> class.
                        /// </summary>
                        /// <param name="target">The target.</param>
                        /// <param name="isValidationEnabled">if set to <c>true</c> [is validation enabled].</param>
                        public FormScopeInfo(string target, bool isValidationEnabled)
                        {
                                this.target = target;
                                this.isValidationEnabled = isValidationEnabled;
                        }

                        /// <summary>
                        /// Gets the root target.
                        /// </summary>
                        /// <value>The root target.</value>
                        public string RootTarget
                        {
                                get { return target; }
                        }

                        /// <summary>
                        /// Gets a value indicating whether this instance is validation enabled.
                        /// </summary>
                        /// <value>
                        ///     <c>true</c> if this instance is validation enabled; otherwise, <c>false</c>.
                        /// </value>
                        public bool IsValidationEnabled
                        {
                                get { return isValidationEnabled; }
                        }
                }

                #endregion

                private static BindingFlags ResolveFlagsToUse(Type type)
                {
                        if (type.Assembly.FullName.StartsWith("DynamicAssemblyProxyGen") || type.Assembly.FullName.StartsWith("DynamicProxyGenAssembly2"))
                        {
                                return PropertyFlags2;
                        }

                        return PropertyFlags;
                }
        }
}