DropDownList联动（经典）

CS :

 1 protected   void  Page_Load( object  sender, System.EventArgs e)
 2          {
 3            if (!IsPostBack)
 4            {
 5                DataSet ds = new DataSet();
 6                ds.ReadXml(Server.MapPath("DataSource.xml"));
 7                for(int i = 0;i <ds.Tables[0].Rows.Count ;i++)
 8                {
 9                    DataRow dr = ds.Tables[0].Rows[i];
10                    Want.Text += String.Format("Group[Groupcount++] = new Array(\"{0}\",\"{1}\",\"{2}\");\n", dr["v_Source"],dr["v_GroupName"].ToString(), dr["v_title"].ToString());
11                    if (SourceList1.Items.FindByText(dr["v_Source"].ToString()) == null)
12                    {
13                        SourceList1.Items.Add(dr["v_Source"].ToString());
14                    }
15                }
16            }
17        }

ASPX:

<% @ Page language="c#" Inherits="TowDropDownList.TowDropDownList" CodeFile="TreeDropDownList.aspx.cs"  %>
<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"  >
< HTML >
     < HEAD >
         < title > TreeDropDownList </ title >
         < meta  content ="Microsoft Visual Studio 7.0"  name ="GENERATOR" >
         < meta  content ="C#"  name ="CODE_LANGUAGE" >
         < meta  content ="JavaScript"  name ="vs_defaultClientScript" >
         < meta  content ="http://schemas.microsoft.com/intellisense/ie5"  name ="vs_targetSchema" >
         < script  language ="javascript" >

        var Wantcount;
        var Groupcount;

        Groupcount=0;

        Group = new Array();
        <asp:Literal id="Want" runat="server"></asp:Literal>

        function changelocation1(locationid)
        {
            document.submit.DirectionList1.length = 0;
            document.submit.WantList1.length = 0;
            var locationid=locationid;
            var i;
            var flag;
            var j;
            for (i=0;i<Groupcount; i++)
            {
                if (Group[i][0] == locationid)
                {
                    flag = true;
                    for (j =0;j<document.submit.DirectionList1.length;j++)
                        if (document.submit.DirectionList1[j].value == Group[i][1])
                            {
                                flag = false;
                                break;
                            }
                    if (flag)
                        document.submit.DirectionList1.options[document.submit.DirectionList1.length]
                        = new Option(Group[i][1], Group[i][1]);
                }
            }
        }


        function changelocation11(locationid, direction)
        {
            document.submit.WantList1.length = 0;
            var locationid=locationid;
            var i;
            var flag;
            var j;
            for (i=0;i<Groupcount;i++)
            {
                if (Group[i][0] == locationid && Group[i][1] == direction)
                {
            
                    flag = true;
                    for (j=0;j<document.submit.WantList1.length;j++)
                        if (document.submit.WantList1[j].value == Group[i][2])
                        {
                            flag = false;
                            break;
                        }
                    if (flag)
                        document.submit.WantList1.options[document.submit.WantList1.length]
                        = new Option(Group[i][2], Group[i][2]);
                }
            }
        }

         </ script >
     </ HEAD >
     < BODY >
         < form  id ="submit"  method ="post"  runat ="server" >
             < TABLE  style ="Z-INDEX: 101; LEFT: 184px; POSITION: absolute; TOP: 144px" >
                 < TR >
                     < TD  style ="WIDTH: 115px; HEIGHT: 17px"  align ="middle" > 求职意向： </ TD >
                     < TD  style ="HEIGHT: 17px" >
                     < asp:dropdownlist  id ="SourceList1"  runat ="server"  DataTextField ="v_source"  DataValueField ="v_source"  onchange ="changelocation1(document.submit.SourceList1.options[document.submit.SourceList1.selectedIndex].value);changelocation11(document.submit.SourceList1.options[document.submit.SourceList1.selectedIndex].value,document.submit.DirectionList1.options[document.submit.DirectionList1.selectedIndex].value)"  Width ="100px" ></ asp:dropdownlist >
                     < asp:dropdownlist  id ="DirectionList1"  runat ="server"  DataValueField ="v_GroupName"  onchange ="changelocation11(document.submit.SourceList1.options[document.submit.SourceList1.selectedIndex].value,document.submit.DirectionList1.options[document.submit.DirectionList1.selectedIndex].value)"  Width ="100px" ></ asp:dropdownlist >
                     < asp:dropdownlist  id ="WantList1"  runat ="server"  DataValueField ="v_title"  Width ="100px" ></ asp:dropdownlist ></ TD >
                 </ TR >
             </ TABLE >
         </ form >
         < script  language ="javascript" >
            changelocation1(document.submit.SourceList1.options[document.submit.SourceList1.selectedIndex].value);
            changelocation11(document.submit.SourceList1.options[document.submit.SourceList1.selectedIndex].value,document.submit.DirectionList1.options[document.submit.DirectionList1.selectedIndex].value)
         </ script >
     </ BODY >
</ HTML >

XML:

< DataSource >
< Data >
< v_Source > 计算机类 </ v_Source >
< v_GroupName > 软件 </ v_GroupName >
< v_title > 程序员 </ v_title >
</ Data >
< Data >
< v_Source > 计算机类 </ v_Source >
< v_GroupName > 软件 </ v_GroupName >
< v_title > 系统分析员 </ v_title >
</ Data >
< Data >
< v_Source > 计算机类 </ v_Source >
< v_GroupName > 软件 </ v_GroupName >
< v_title > 项目经理 </ v_title >
</ Data >
< Data >
< v_Source > 计算机类 </ v_Source >
< v_GroupName > 硬件 </ v_GroupName >
< v_title > 网络工程师 </ v_title >
</ Data >
< Data >
< v_Source > 计算机类 </ v_Source >
< v_GroupName > 硬件 </ v_GroupName >
< v_title > 计算机维护 </ v_title >
</ Data >
< Data >
< v_Source > 计算机类 </ v_Source >
< v_GroupName > 数据库 </ v_GroupName >
< v_title > 数据库开发 </ v_title >
</ Data >
< Data >
< v_Source > 计算机类 </ v_Source >
< v_GroupName > 数据库 </ v_GroupName >
< v_title > 数据库管理 </ v_title >
</ Data >
< Data >
< v_Source > 行政/管理类 </ v_Source >
< v_GroupName > 行政 </ v_GroupName >
< v_title > 文秘 </ v_title >
</ Data >
< Data >
< v_Source > 行政/管理类 </ v_Source >
< v_GroupName > 行政 </ v_GroupName >
< v_title > 助理 </ v_title >
</ Data >
< Data >
< v_Source > 行政/管理类 </ v_Source >
< v_GroupName > 管理 </ v_GroupName >
< v_title > 总经理 </ v_title >
</ Data >
< Data >
< v_Source > 行政/管理类 </ v_Source >
< v_GroupName > 管理 </ v_GroupName >
< v_title > 部门经理 </ v_title >
</ Data >
< Data >
< v_Source > 行政/管理类 </ v_Source >
< v_GroupName > 管理 </ v_GroupName >
< v_title > 总监 </ v_title >
</ Data >
</ DataSource >