学习Ajax的简单联动小实例

来源：互联网发布：怀化网络教育编辑：程序博客网时间：2024/05/16 08:31

实例就只有两个页面：DynamicList.htm和WebForm2.aspx
DynamicList.htm

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title></title>
<meta name="GENERATOR" content="Microsoft Visual Studio .NET 7.1">
<meta name=ProgId content=VisualStudio.HTML>
<meta name=Originator content="Microsoft Visual Studio .NET 7.1">
<script language=javascript>
var xmlHttp;
//创建XmlHttp对象
function createXMLHttpRequest(){
if(window.ActiveXObject){
  xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
else if(window.XMLHTTPRequest){
  xmlHttp = new XMLHTTPRequest();
}
}
//省份列表改变时所触发的事件
function ProvinceChange(){
clearCityList();
createXMLHttpRequest();
var ProvinceCode= document.getElementById("ProvinceList").value;
var url   = "WebForm2.aspx?ProvinceCode="+ProvinceCode+"&CurrentTime="+new Date().getTime();
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.open("GET",url,true);
xmlHttp.send(null);
}
//当服务器有数据返回时调用refreshCityList方法来刷新城市列表
function handleStateChange(){
if(xmlHttp.readyState == 4){
  if(xmlHttp.status == 200){
   refreshCityList();
  }
}
}
//根据返回的数据加载新的数据到城市列表
function refreshCityList(){
clearCityList();
var city = document.getElementById("CityList");
var Results = xmlHttp.responseXML.getElementsByTagName("city");
var option = null;
for(var i = 0; i < results.length;i++){
  option = document.createElement("option");
  option.appendChild(document.createTextNode(Results.firstChild.nodeValue));
  city.appendChild(option);
}
}
//清除城市列表
function clearCityList(){
var city = document.getElementById("CityList");
while (city.childNodes.length > 0){
  city.removeChild(city.childNodes[0]);
}
}
</script>
</head>
<body>
  <form id="Form1" method="post" runat="server">
   <select id="ProvinceList" onchange="ProvinceChange();" NAME="ProvinceList">
    <option value="0">---请选择---</option>
    <option value="0311">河北省</option>
    <option value="0351">山西省</option>
    <option value="0471">内蒙古自治区</option>
    <option value="025">江苏省</option>
   </select>
   <select id="CityList" NAME="CityList">
    <option value="0">---请选择---</option>
   </select>
  </form>

</body>
</html>

上面的代码中ProvinceChange函数将数据提交到WebForm2.aspx页面，WebForm2.aspx根据传入的参数来返回相关数据。
WebForm2.aspx---html部分代码

<%@ Page language="c#" Codebehind="WebForm2.aspx.cs" AutoEventWireup="false" Inherits="AjaxSite.WebForm2" %>
[/code]
注意，我这里把WebForm2.aspx的html代码剔除只剩下一个头信息的原因见另外的帖子：
http://blog.tn99.com/blogview.asp?logID=255

WebForm2.aspx---cs部分代码
[code]
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.IO;

namespace AjaxSite
{
/// <summary>
/// WebForm2 的摘要说明。
/// </summary>
public class WebForm2 : System.Web.UI.Page
{
  protected System.Web.UI.WebControls.Button Button1;

  private void Page_Load(object sender, System.EventArgs e)
  {
   string ProvinceCode  = Request.QueryString["ProvinceCode"]==null?"0":Request.QueryString["ProvinceCode"].ToString();
   Response.ContentType = "text/xml";
   string XmlStr   = "<citylist>";
   switch(ProvinceCode)
   {
    case "0":
     XmlStr = XmlStr+"<city>---请选择---</city>";
     break;
    case "0311":
     XmlStr = XmlStr+"<city>石家庄</city>";
     XmlStr = XmlStr+"<city>张家口</city>";
     XmlStr = XmlStr+"<city>承德</city>";
     XmlStr = XmlStr+"<city>秦皇岛</city>";
     break;
    case "0351":
     XmlStr = XmlStr+"<city>太原</city>";
     XmlStr = XmlStr+"<city>大同</city>";
     XmlStr = XmlStr+"<city>朔州</city>";
     XmlStr = XmlStr+"<city>阳泉</city>";
     break;
    case "0471":
     XmlStr = XmlStr+"<city>呼和浩特</city>";
     XmlStr = XmlStr+"<city>包头</city>";
     XmlStr = XmlStr+"<city>乌海</city>";
     XmlStr = XmlStr+"<city>赤峰</city>";
     break;
    case "025":
     XmlStr = XmlStr+"<city>南京</city>";
     XmlStr = XmlStr+"<city>徐州</city>";
     XmlStr = XmlStr+"<city>连云港</city>";
     XmlStr = XmlStr+"<city>宿迁</city>";
     break;
   }
   XmlStr = XmlStr+"</citylist>";
   Response.Write(XmlStr);
  }

  #region Web 窗体设计器生成的代码
  override protected void OnInit(EventArgs e)
  {
   //
   // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
   //
   InitializeComponent();
   base.OnInit(e);
  }

  /// <summary>
  /// 设计器支持所需的方法 - 不要使用代码编辑器修改
  /// 此方法的内容。
  /// </summary>
  private void InitializeComponent()
  {
   this.Load += new System.EventHandler(this.Page_Load);
  }
  #endregion
}
}