Microsoft Asp.Net Ajax框架入门(12) 了解异步通信层

VS 2008

本文通过两个简单的例子，了解Asp.Net Ajax Asynchronous Communication Layer

Asp.Net Ajax异步通信层提供了一系列客户端的类，用于客户端请求服务端

第一个例子：请求服务端页面
1） 被请求页 Ajax_GetUserName.aspx
    html代码仅留页面声明，其余全部清楚：

<% @ Page Language = " C# "  AutoEventWireup = " true "  CodeFile = " Ajax_GetUserName.aspx.cs "  Inherits = " Ajax_GetUserName "   %>

    Ajax_GetUserName.aspx.cs页面写处理逻辑：

public   partial   class  Ajax_GetUserName : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (Request.QueryString["userId"] == "1") {
            Response.Write("guozhijian");
        }
        else {
            Response.Write(string.Empty);
        }
    }
}

2） 客户端请求

<% @ Page Language = " C# "  AutoEventWireup = " true "   CodeFile = " Default.aspx.cs "  Inherits = " _Default "   %>

<! 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 > Untitled Page </ title >
     < script type = " text/javascript " >
        function btnGetNameClickHandler()  {
            var req = new Sys.Net.WebRequest();
            req.set_url("Ajax_GetUserName.aspx?userId=1");
            req.add_completed(requestCompleted);
            req.invoke();
        }
        function requestCompleted(executor, eventArgs)  {
            if(executor.get_statusCode() == 200) {
                alert(executor.get_responseData());
            }
        }
     </ script >
</ head >
< body >
     < form id = " form1 "  runat = " server " >
     < asp:ScriptManager ID = " smgr "  runat = " server " ></ asp:ScriptManager >
     < div >
         < input type = " button "  id = " btnGetName "  onclick = " btnGetNameClickHandler() "  value = " get name "   />
     </ div >
     </ form >
</ body >
</ html >

第二个例子：请求XML文档
1）新建UserInfos.xml

<? xml version = " 1.0 "  encoding = " utf-8 "   ?>
< userInfos >
   < userInfo >
     < userId > 1 </ userId >
     < userName > guozhijian </ userName >
   </ userInfo >
   < userInfo >
     < userId > 2 </ userId >
     < userName > zhenglanzhen </ userName >
   </ userInfo >
</ userInfos >

2）客户端请求

function btnGetXmlClickHandler()  {
            var req = new Sys.Net.WebRequest();
            req.set_url("UserInfos.xml");
            req.add_completed(getXmlCompleted);
            req.invoke();    
        }
        function getXmlCompleted(executor, eventArgs)  {
            if(executor.get_statusCode() == 200) {
                alert(executor.get_xml().xml);
            }
        }