sdk/samples/all in on code/Visual Studio 2010/CSDynamicallyBuildLambdaExpressionWithField/MainForm.cs

   1 /********************************** Module Header **********************************\
   2 * Module Name:  MainForm.cs
   3 * Project:      CSDynamicallyBuildLambdaExpressionWithField
   4 * Copyright (c) Microsoft Corporation.
   5 *
   6 * This sample demonstrates how to dynamically build lambda expression and show data
   7 * into DataGridView Control.
   8 *
   9 * This sample shows up multiple conditions jointing together and dynamically
  10 * generate  LINQ TO SQL. LINQ is a great way to declaratively filter and query data
  11 * in a Type_Safe,Intuitive,and very expressive way.this sample achieve it. For example,
  12 * the search feature in this application allow the customer to find all records that
  13 * meet criteria defined on multiple columns.
  14 *
  15 * This source is subject to the Microsoft Public License.
  16 * See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
  17 * All other rights reserved.
  18 *
  19 * THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
  20 * EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF
  21 * MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
  22 \***********************************************************************************/
  23
  24 using System;
  25 using System.Linq;
  26 using DynamicCondition;
  27
  28
  29 namespace CSDynamicallyBuildLambdaExpressionWithField
  30 {
  31     public partial class MainForm
  32     {
  33         internal MainForm()
  34         {
  35             InitializeComponent();
  36         }
  37         private NorthwindDataContext db = new NorthwindDataContext();
  38
  39         /// <summary>
  40         /// Load the list of fields into the control when Winform loads.
  41         /// </summary>
  42         private void MainForm_Load(object sender, EventArgs e)
  43         {
  44             // Load the list of fields into the control
  45             ConditionBuilder1.SetDataSource(db.Orders);
  46         }
  47
  48         /// <summary>
  49         /// Dynamically generate LINQ query and put it into DataGridView Control
  50         /// </summary>
  51         private void btnSearch_Click(object sender, EventArgs e)
  52         {
  53             // Get the Condition out of the control
  54             var c = ConditionBuilder1.GetCondition<Order>();
  55
  56             // Filter out all Orders that don't match the Condition
  57             // Note that the query does not actually get executed yet to due to deferred execution
  58             var filteredQuery = db.Orders.Where(c);
  59
  60             // We can now perform any other operations (such as Order By or Select) on filteredQuery
  61             var query = from row in filteredQuery
  62                         orderby row.OrderDate, row.OrderID
  63                         select row;
  64
  65             // Executes the query and displays the results in DataGridView1
  66             dgResult.DataSource = query;
  67         }
  68
  69         /// <summary>
  70         /// Property DefaultInstance
  71         /// </summary>
  72         private static MainForm _defaultInstance;
  73         public static MainForm DefaultInstance
  74         {
  75             get
  76             {
  77                 if (_defaultInstance == null)
  78                     _defaultInstance = new MainForm();
  79                 return _defaultInstance;
  80             }
  81         }
  82     }
  83
  84 }