[转] ASP.NET使用AJAX联动
数据库
CREATE TABLE [dbo].[LinkAge01] (
[id] [int] IDENTITY (1, 1) NOT NULL ,
[name] [varchar] (50) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[LinkAge02] (
[id] [int] IDENTITY (1, 1) NOT NULL ,
[lID] [int] NOT NULL ,
[name] [varchar] (50) COLLATE Chinese_PRC_CI_AS NOT NULL
) ON [PRIMARY]
GO
页面index.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="index.aspx.cs" Inherits="_index" %>
<html>
<head runat="server">
<title>LinkAgeTest.</title>
<script language="javascript">
//jb函数会根据不同的浏览器初始化个xmlhttp对象
function jb()
{
var A=null;
try
{
A=new ActiveXObject("Msxml2.XMLHTTP");
}
catch(e)
{
try
{
A=new ActiveXObject("Microsoft.XMLHTTP");
}
catch(oc)
{
A=null
}
}
if ( !A && typeof XMLHttpRequest != "undefined" )
{
A=new XMLHttpRequest()
}
return A
}
//下面Go函数是父列表框改变的时候调用，参数是选择的条目
function Go()
{
var svalue = document.getElementById("ddl01").value;//得到选择框的下拉列表的value
var weburl = "index.aspx?id="+svalue;//定义要处理数据的页面
var xmlhttp = jb();//初始化个xmlhttp对象
xmlhttp.open("get",weburl,true); //提交数据，第一个参数最好为get，第三个参数最好为true
//alert(xmlhttp.responseText);
//如果已经成功的返回了数据
xmlhttp.onreadystatechange=function()
{
if(xmlhttp.readyState==4)//4代表成功返回数据
{
var result = xmlhttp.responseText;//得到服务器返回的数据
document.getElementById("ddl02").length = 0;//先清空ddlC的所有下拉项
document.getElementById("ddl02").options.add(new Option("请选择","0")); //给ddlC加个全部型号的,注意是Option不是option
if(result!="")//如果返回的数据不是空
{
var allArray = result.split(",");//把收到的字符串按照，分割成数组
//循环这个数组，注意是从1开始，因为收到的字符串第一个字符是，号，所以分割后第一个数组为空
for(var i=1;i<allArray.length;i++)
{
var thisArray = allArray[i].split("|");//在把这个字符串按照|分割成数组
//为ddlC添加条目
document.getElementById("ddl02").options.add(new Option(thisArray[0].toString(),thisArray[1].toString()));
}
}
}
}
//发送数据，请注意顺序和参数，参数一定为null或者""
xmlhttp.send(null);
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
省：<select id="ddl01" name="ddl01" runat="server" onchange="Go(this)"></select>
市：<select id="ddl02" name="ddl02" runat="server" ></select>
<%--
省：<asp:dropdownlist ID="ddl01" runat="server" onchange="Go(this)"></asp:dropdownlist>
市：<asp:dropdownlist ID="ddl02" runat="server"></asp:dropdownlist>
--%>
<asp:Button ID="btnOk" runat="server" Text=" 确 定 " OnClick="btnOk_Click" />
</div>
</form>
</body>
</html>
类文件 index.cs
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
public partial class _index : System.Web.UI.Page
{
private SqlConnection con;
private SqlDataAdapter sda;
private SqlCommand cmd;
private DataSet ds;
private SqlDataReader sdr;
//数据库开连接字符串
public static String conStr = "server=.; database=Test; uid=sa; pwd=sa";
protected void Page_Load(object sender, EventArgs e)
{
try
{
if (!IsPostBack)
{
con = new SqlConnection(conStr);
sda = new SqlDataAdapter("select * from LinkAge01", con);
ds = new DataSet();
sda.Fill(ds, "LinkAge01");
ds.Tables["LinkAge01"].DefaultView.Sort = "id asc";
ddl01.DataSource = ds.Tables["LinkAge01"].DefaultView;
ddl01.DataValueField = "id";
ddl01.DataTextField = "name";
ddl01.DataBind();
}
Response.Write("Request.Form[ddl02]:" + Request.Form["ddl02"] + "<br />");
BindDrop();
}
catch (Exception ex)
{
Response.Write("error:" + ex.ToString());
}
}
protected void btnOk_Click(object sender, EventArgs e)
{
try
{
Response.Write(ddl01.Items[ddl01.SelectedIndex].Text + "<br/>");
Response.Write(ddl02.Items[ddl02.SelectedIndex].Text + "<br/>");
}
catch (Exception ex)
{
Response.Write("error:" + ex.ToString());
}
}
protected void BindDrop()
{
String str = Request.QueryString["id"];
String str1 = ddl01.Items[ddl01.SelectedIndex].Value;
Response.Write("str1=" + str1 + "<br/>");
String a = str + "abc";
if (str + "abc" != "abc")//如果str加个字符串!=原来的字符串则说明触发过ddlS的onchange事件
BindChild(str);//触发过ddlS的onchange事件
else
BindParent(str1);//第一次加载活刷新
}
protected void BindParent(String str1)
{
try
{
//如果是第一次请求或者是刷新这个页面则根据ddlS的值来选择
//把参数转化成int
int i = Convert.ToInt32(str1);
ddl02.Items.Clear();
ddl02.Items.Add(new ListItem("请选择", "0"));
con = new SqlConnection(conStr);
cmd = new SqlCommand("select * from LinkAge02 where lID=" + i, con);
con.Open();
sdr = cmd.ExecuteReader();
while (sdr.Read())
{
ddl02.Items.Add(new ListItem(sdr["name"].ToString(), sdr["id"].ToString()));
}
sdr.Close();
con.Close();
ddl02.Items[0].Selected=true;
ddl01.Items[0].Selected = false;
//添加下面这话的意思是当点提交按钮提交窗体的时候第二个ddl02的状态能够得到保存
Response.Write("Request.Form[ddl02]:"+Request.Form["ddl02"]+"<br />");
ddl02.Value = Request.Form["ddl02"];
}
catch (Exception ex)
{
Response.Write("error:" + ex.ToString());
}
}
protected void BindChild(String str)
{
//通过js给包括dropdownlist任何控件添加的内容不会被保存状态
//把参数转化成int
int i = Convert.ToInt32(str);
String result = "";
Response.Clear();
con = new SqlConnection(conStr);
cmd = new SqlCommand("select * from LinkAge02 where lID=" + i, con);
con.Open();
sdr = cmd.ExecuteReader();
while (sdr.Read())
{
result += "," + sdr["name"].ToString() + "|" + sdr["id"].ToString();
}
sdr.Close();
con.Close();
Response.Write(result);
Response.Flush();
Response.Close();
}
}
原文地址：http://blog.csdn.net/mathew3625/archive/2008/04/13/2288707.aspx
