MonoRail/Castle.MonoRail.Framework/ViewComponents/CaptureFor.cs

   1 // Copyright 2004-2007 Castle Project - http://www.castleproject.org/
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 //     http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15 namespace Castle.MonoRail.Framework.ViewComponents
  16 {
  17         using System;
  18         using System.IO;
  19         using System.Text;
  20
  21         /// <summary>
  22         /// Renders the inner content and stores it in the IViewEngineContext
  23         /// <code>
  24         /// #blockcomponent(CaptureFor with "id=someId" ["append=before"])
  25         ///             content to be captured
  26         /// #end
  27         ///
  28         /// ${someId}
  29         /// </code>
  30         /// id - the key to be used to retrieve the captured contents
  31         /// append - when present will append component content into the current
  32         ///                      content, if append = "before" will append before the current content
  33         /// </summary>
  34         public class CaptureFor : ViewComponent
  35         {
  36                 /// <summary>
  37                 /// Render component's content and stores it in the view engine ContextVars
  38                 /// so it can be reference and included in other places
  39                 /// </summary>
  40                 public override void Render()
  41                 {
  42                         String id = (String)Context.ComponentParameters["id"];
  43
  44                         if (id == null || id.Trim().Length == 0)
  45                         {
  46                                 throw new MonoRailException("CaptureFor requires an id attribute use #blockcomponent(CaptureFor with \"id=someid\")...#end");
  47                         }
  48
  49                         StringWriter buffer = new StringWriter();
  50
  51                         Context.RenderBody(buffer);
  52
  53
  54                         String currentContent = Context.ContextVars[id] as string;
  55                         StringBuilder sb = buffer.GetStringBuilder();
  56                         String appendAtt = Context.ComponentParameters["append"] as string;
  57
  58                         if (appendAtt != null)
  59                         {
  60                                 if (appendAtt == "before")
  61                                 {
  62                                         sb.Append(currentContent);
  63                                 }
  64                                 else
  65                                 {
  66                                         sb.Insert(0, currentContent);
  67                                 }
  68                         }
  69
  70                         Context.ContextVars[id] = sb.ToString();
  71
  72                         //This makes sure that Brail would bubble the content
  73                         //up to a parent view if called from a sub view.
  74                         Context.ContextVars[id + ".@bubbleUp"] = true;
  75                 }
  76         }
  77 }