treeView控件实例--Ajax局部刷新

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结合数据库获得父节点和子节点信息数值：

.aspx代码如下：

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="TreeView控件.aspx.cs" Inherits="TreeView控件" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server">    <title></title>    <style type="text/css">    .fl{ float:left;}    .fr{ float:right;}    .clr{ clear:both;}    </style></head><body>    <form id="form1" runat="server">    <div>    <div id="div_treeview" class="fl">    <%=DateTime.Now.ToLongTimeString() %>            <asp:TreeView ID="TreeView1" runat="server" ExpandDepth="0"             onselectednodechanged="TreeView1_SelectedNodeChanged">        </asp:TreeView>    </div>    <div id="others" class="fr">    <%--为了不使整个页面刷新，引入ajax局部刷新,提高显示速度。以下是标准程序：    <asp:ScriptManager ID="ScriptManager2" runat="server">        </asp:ScriptManager>        <asp:UpdatePanel ID="UpdatePanel2" runat="server">        <ContentTemplate>       此处填入内容         </ContentTemplate>         <Triggers>        <asp:AsyncPostBackTrigger ControlID="TreeView1" />        </Triggers>            </asp:UpdatePanel>--%>             <asp:ScriptManager ID="ScriptManager1" runat="server">        </asp:ScriptManager>        <asp:UpdatePanel ID="UpdatePanel1" runat="server">        <ContentTemplate>        <%=DateTime.Now.ToLongTimeString() %>        TEXT:<asp:Label ID="lbl_TEXT" runat="server" Text="Label"></asp:Label>    VALUE:<asp:Label ID="lbl_VALUE" runat="server" Text="Label"></asp:Label>    VALUEPATH:<asp:Label ID="lbl_VALUEPATH" runat="server" Text="Label"></asp:Label>        </ContentTemplate>        <Triggers>        <asp:AsyncPostBackTrigger ControlID="TreeView1" />        </Triggers>        </asp:UpdatePanel>            </div>    <div class="clr">        </div>            </div>    </form></body></html>

.aspx.cs代码如下：

using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using System.Data.SqlClient;public partial class TreeView控件 : System.Web.UI.Page{    string con = "server=localhost\\SQL2005 ;uid=sa;pwd=1111qq;database=DBPromary";    SqlConnection conn;    SqlCommand cmd;    SqlDataReader datar;    string str_sql;    protected void Page_Load(object sender, EventArgs e)    {        if (!IsPostBack) {            maketree();        }    }    protected void maketree() {        //省        TreeNode _tNode,_ParentNode;        conn = new SqlConnection(con);        conn.Open();        str_sql="select * from promary";        cmd = new SqlCommand(str_sql, conn);        datar = cmd.ExecuteReader();        while (datar.Read()){        _tNode=new TreeNode();//实例化结点            _tNode.Text=datar["proName"].ToString();            _tNode.Value="p_"+datar["proID"].ToString();            TreeView1.Nodes.Add(_tNode);//结点加到TreeView上        }        conn.Close();        //city        conn = new SqlConnection(con);        conn.Open();        str_sql = "select * from city";        cmd = new SqlCommand(str_sql, conn);        datar = cmd.ExecuteReader();        while (datar.Read())        {            _ParentNode = TreeView1.FindNode("p_"+datar["proID"].ToString());//寻找父节点            _tNode=new TreeNode();//实例化子节点            _tNode.Text=datar["cityName"].ToString();//子节点的显示            _tNode.Value="c_"+datar["cityID"].ToString();//子节点的数值            _ParentNode.ChildNodes.Add(_tNode);//将子节点加到找到的父节点上        }        conn.Close();    }    protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)    {        TreeNode _tnode = TreeView1.SelectedNode;//SelectedNode方法找到选中的结点        lbl_TEXT.Text = _tnode.Text;        lbl_VALUE.Text = _tnode.Value;        lbl_VALUEPATH.Text = _tnode.ValuePath;    }}

效果如下图：

引入Ajax之后只会刷新部分页面，通过时间条的刷新可以看出。这样会提高页面刷新效率。

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