Web下TreeView同一节点连续点击，只执行一次SelectedNodeChanged的解决

http://blog.csdn.net/net_boy/archive/2009/11/05/4772227.aspx

一、本章主要介绍.NET一个小技巧，在web下的TreeeView，当对一个节点进行SelectedNodeChanged后，如果再次连续单击这个节点，则SelectedNodeChanged不会再触发，为了使SelectedNodeChanged每次都执行，要进行如下操作：
在SelectedNodeChanged事件里，对选中的节点马上将其Selected属性置为false

二、具体例子如下：
我的Web应用的名字为MingXu.WebSite，我在根目录下见了一个目录Controls，用来放WebUserControl，我的例子就是一个WebUserControl。

WebUserControl代码如下：
1、前台页面内容：
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="ucTreeList.ascx.cs" Inherits="MingXu.WebSite.Controls.ucTreeList" %>
<asp:TreeView ID="tvTest" runat="server"
    onselectednodechanged="tvTest_SelectedNodeChanged">
</asp:TreeView>
<p>
    显示选中节点的Text:<asp:TextBox ID="txtSelectedNodeText" runat="server"></asp:TextBox>
    节点单击计数器:<asp:TextBox ID="txtCount" runat="server"></asp:TextBox>
</p>

2、后台文件：
//******************************************************
//文件名：ucTreeList.ascx
//功能：Web下TreeView同一节点连续点击，只执行一次SelectedNodeChanged的解决
//作者：*
//日期：2009-11-4
//*******************************************************

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

namespace MingXu.WebSite.Controls
{
    public partial class ucTreeList : System.Web.UI.UserControl
    {
        private static int _count = 0;

/// <summary>
        /// 功能：构造一个树
        /// 作者：Jerry
        /// 日期：2009-11-4
        /// </summary>
        private void LoadTree()
        {
            tvTest.Nodes.Clear();

TreeNode rootNode = null;
TreeNode pNode1 = null;
TreeNode pNode2 = null;

rootNode = new TreeNode("Root");

            pNode1 = new TreeNode("pNode1");
            pNode1.ChildNodes.Add(new TreeNode("Node1"));
            pNode1.ChildNodes.Add(new TreeNode("Node2"));

pNode2 = new TreeNode("pNode2");
pNode2.ChildNodes.Add(new TreeNode("Node3"));
pNode2.ChildNodes.Add(new TreeNode("Node4"));

rootNode.ChildNodes.Add(pNode1);
rootNode.ChildNodes.Add(pNode2);

tvTest.Nodes.Add(rootNode);
}

/// <summary>
        /// 功能：加载树
        /// 作者：Jerry
        /// 日期：2009-11-4
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
                LoadTree();
        }

/// <summary>
        /// 功能：树节点SelectedNodeChanged事件
        /// 作者：Jerry
        /// 日期：2009-11-4
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void tvTest_SelectedNodeChanged(object sender, EventArgs e)
        {
            txtSelectedNodeText.Text = tvTest.SelectedNode.Text;
            txtCount.Text = _count++.ToString();
            //置选中节点的Selected属性为false
            tvTest.SelectedNode.Selected = false;

        }
    }
}

3、资源文件：
//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//     Runtime Version:2.0.50727.3603
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

namespace MingXu.WebSite.Controls {


    public partial class ucTreeList {

        /// <summary>
        /// tvTest control.
        /// </summary>
        /// <remarks>
        /// Auto-generated field.
        /// To modify move field declaration from designer file to code-behind file.
        /// </remarks>
        protected global::System.Web.UI.WebControls.TreeView tvTest;

        /// <summary>
        /// txtSelectedNodeText control.
        /// </summary>
        /// <remarks>
        /// Auto-generated field.
        /// To modify move field declaration from designer file to code-behind file.
        /// </remarks>
        protected global::System.Web.UI.WebControls.TextBox txtSelectedNodeText;

        /// <summary>
        /// txtCount control.
        /// </summary>
        /// <remarks>
        /// Auto-generated field.
        /// To modify move field declaration from designer file to code-behind file.
        /// </remarks>
        protected global::System.Web.UI.WebControls.TextBox txtCount;
    }
}

4、新建一个WebForm，把这个用户控件拖进去，然后，把这个页设为默认页，启动运行就能看到结果，结果页面如下：

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