求无刷新二级联动菜单（读数据库，最好XML的）

Question

看过一些网上介绍的．但本人刚学．不太懂，希望大家帮帮我：
－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－
Manager.RelationsList();//读第一个下拉框的值的方法
Manager.RelationsList(ID);//读第二个下拉框的值的方法
//第一个下拉框的绑定
｛
DataSet myds1 = Manager.RelationsList();
this.DropDownList1.DataSource = myds1.Tables[0];
this.DropDownList1.DataBind();
}－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－
我要怎么写实现无刷新效果，第二个是根据第一个选择的ID传到
我自己写的Manager.RelationsList(ID);方法里读出数据的
分数不多，希望大家帮帮忙，解决就结！急哈，

Answer 1

   <script language="javascript" type="text/javascript">
    var xmlHttp;
function createXMLHttpRequest()
{
     if(window.ActiveXObject)
     {
        xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
     }
     else if(window.XMLHttpRequest)
     {
        xmlHttp=new XMLHttpRequest();
     }
}
    
    ///以下是获取类别
    function GetEndSort()
    {
        var subSortID=document.getElementById("ddlSubSort").value;
          createXMLHttpRequest();
     var queryString="../CommonWeb/GetEndSort.aspx?SubSortID=" + subSortID + "&timeStamp=" + new Date().getTime();
     xmlHttp.onreadystatechange=SubSortChange;
     xmlHttp.open("GET",queryString,true);
     xmlHttp.send(null);
    }    
function SubSortChange()
{
    if(xmlHttp.readyState==4)
    {
        if(xmlHttp.status==200)
        {
            var str=xmlHttp.responseText;
             var t1=str.split(';');
    document.getElementById("ddlEndSort").options.length=0;
    
        var optTitle=document.createElement("OPTION");
         optTitle.value="-1";
         optTitle.innerHTML="不再选择";
         document.getElementById("ddlEndSort").appendChild(optTitle);    
         
    for(var i=0;i<t1.length-1;i++)
    {  
        var t2=t1[i].split(',');        
        
        var optEndSort=document.createElement("OPTION");
         optEndSort.value=t2[0];
         optEndSort.innerHTML=t2[1];
         document.getElementById("ddlEndSort").appendChild(optEndSort);    
         
    }
        }
    }
}
    </script>-------------------------------------------------                                      <asp:DropDownList ID="ddlSubSort" runat="server" onchange="GetEndSort()">
                                      </asp:DropDownList>
                                      <asp:DropDownList ID="ddlEndSort" runat="server">
                                      </asp:DropDownList>

Answer 2

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;
using System.Text;
using System.Data.SqlClient;public partial class CommonWeb_GetEndSort : System.Web.UI.Page
{
    UserTable ut = new UserTable();
    protected void Page_Load(object sender, EventArgs e)
    {
        StringBuilder sb = new StringBuilder("");
        if (Request.QueryString["subSortID"] != null)
        {
            SqlDataReader myRead = ut.GetDataReader("Select SortID,SortName from Sort where ParentID=" + Request.QueryString["subSortID"].ToString());
            while (myRead.Read())
            {
                sb.Append(myRead["SortID"].ToString() + "," + myRead["SortName"].ToString() + ";");
            }
            myRead.Close();
        }
        Response.Write(sb.ToString());
        Response.End();
    }
}

Answer 3

<title>省市县三级联动</title>
    <script type="text/javascript">
        function ddl_getcity(obj)
        {
            var List=document.getElementById("ddlProvince");
            var index=List.selectedIndex;
            var pro=List.options[index].value;
            Province.GetCity(pro,GetCity_CallBack);
        }
        function GetCity_CallBack(result)
        {
            var ds=result.value;
            if(ds !=null && typeof(ds)=="object" && ds.Tables !=null)
            {
                var List=document.getElementById("ddlCity");
                for(var i=0;i<List.options.length-1;i++)
                {
                    List.options.remove(i);
                    
                }
                for(var i=0;i<ds.Tables[0].Rows.length;i++)
                {
                    List.options.add(new Option(ds.Tables[0].Rows[i].City.toString(),ds.Tables[0].Rows[i].CityID.toString()));
                    
                }
            }
            else 
            { 
                        alert("Error:" + result.request.responseText); 
                    }
        }
        function ddl_getarea(obj)
                {
                    var list=document.getElementById("ddlCity");
                    var index = list.selectedIndex;
                    var pValue = list.options[index].value;
                    //alert(pValue);
                    Province.GetArea(pValue, GetArea_CallBack);
                }
                //县的回调函数
                function GetArea_CallBack(response){
                    var ds = response.value;
                    if(ds != null && typeof(ds) == "object" && ds.Tables != null){
                        var list=document.getElementById("ddlArea");
                        for (var i=list.options.length-1;i>=0;i--)
                        {
                            list.options.remove(i);                        
                        }
                        for(var i=0; i<ds.Tables[0].Rows.length; i++)
                        {
                            list.options.add(new Option(ds.Tables[0].Rows[i].aera.toString(),ds.Tables[0].Rows[i].areaID.toString()))        
                        }
                    }
                    else { 
                        alert("Error:" + response.request.responseText); 
                    }
                }                </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:DropDownList ID="ddlProvince" runat="server">
        </asp:DropDownList>
        <asp:DropDownList ID="ddlCity" runat="server">
        </asp:DropDownList>
        <asp:DropDownList ID="ddlArea" runat="server">
        </asp:DropDownList><title>省市县三级联动</title>
    <script type="text/javascript">
        function ddl_getcity(obj)
        {
            var List=document.getElementById("ddlProvince");
            var index=List.selectedIndex;
            var pro=List.options[index].value;
            Province.GetCity(pro,GetCity_CallBack);
        }
        function GetCity_CallBack(result)
        {
            var ds=result.value;
            if(ds !=null && typeof(ds)=="object" && ds.Tables !=null)
            {
                var List=document.getElementById("ddlCity");
                for(var i=0;i<List.options.length-1;i++)
                {
                    List.options.remove(i);
                    
                }
                for(var i=0;i<ds.Tables[0].Rows.length;i++)
                {
                    List.options.add(new Option(ds.Tables[0].Rows[i].City.toString(),ds.Tables[0].Rows[i].CityID.toString()));
                    
                }
            }
            else 
            { 
                        alert("Error:" + result.request.responseText); 
                    }
        }
        function ddl_getarea(obj)
                {
                    var list=document.getElementById("ddlCity");
                    var index = list.selectedIndex;
                    var pValue = list.options[index].value;
                    //alert(pValue);
                    Province.GetArea(pValue, GetArea_CallBack);
                }
                //县的回调函数
                function GetArea_CallBack(response){
                    var ds = response.value;
                    if(ds != null && typeof(ds) == "object" && ds.Tables != null){
                        var list=document.getElementById("ddlArea");
                        for (var i=list.options.length-1;i>=0;i--)
                        {
                            list.options.remove(i);                        
                        }
                        for(var i=0; i<ds.Tables[0].Rows.length; i++)
                        {
                            list.options.add(new Option(ds.Tables[0].Rows[i].aera.toString(),ds.Tables[0].Rows[i].areaID.toString()))        
                        }
                    }
                    else { 
                        alert("Error:" + response.request.responseText); 
                    }
                }                </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:DropDownList ID="ddlProvince" runat="server">
        </asp:DropDownList>
        <asp:DropDownList ID="ddlCity" runat="server">
        </asp:DropDownList>
        <asp:DropDownList ID="ddlArea" runat="server">
        </asp:DropDownList>

Answer 4

上面这些代码我网上搜到也很多．我看的不是很明白才来提问一下哈．~.~
希望能结合我上面的帮我稍稍改动一下，二级联动就行了．．．．．．．．．．．．．．．．．．．．．．．．．
Manager.RelationsList();//读第一个下拉框的值的方法 
Manager.RelationsList(ID);//读第二个下拉框的值的方法 
．．．．．．．．．．．．．．．．．．．．．．．．．．．
上两个方法是我写的读取数据的方法，帮帮忙，帮我解决一下．或者注释多点的细点的例子给个
现在在上班，没什么时间一个个试过去，晚上才能试了，希望能给个简单好点的解决方法
再次谢谢哈

Answer 5

楼上的说的道理我明白，但我做了半天多了．用AJAX已经实现效果，但选择提交后页面出现回调错误，查了很多方法，基本无法解决，我朋友叫我使用XML读取，这种方式会合理些，我想试一下，但本人愚昧，网上的一时理解不了，希望高手能指点一下，做程序感觉有时候自己怎么想也想不出，但有人提点一下可能就是一句代码的问题，返回来看就感觉很简单了，
所以希望能指点一下，

Answer 6

据我所知,如果在.net中实现这个功能,可以简单一点用客户端回调就可以搞定了.
还可以使用asp.net ajax框架.

Answer 7

顶楼上的楼上，NET是够强悍..

Answer 8

asp.net ajax的CascadingDropDown控件就是这个作用,用它吧,我用它做过三级联动

Answer 9

http://blog.csdn.net/wxg22526451/archive/2008/04/24/2323244.aspx

Answer 10

var pro=xmldoc.selectSingleNode("//addrss/proc[@name='"++"']");
var child=proNode.childNodes.length;
for(var i=0;i<child;i++){
var cityname=
}