Microsoft ASP. NET Ajax framework (12) Introduction to the asynchronous communication layer

Vs 2008

This article uses two simple examples to understand ASP. NET Ajax asynchronous communication layer

The ASP. NET Ajax asynchronous communication layer provides a series of client classes for the client to request the server.

Example 1: Request the Server Page
1) requested page: ajax_getusername.aspx
Html Code Only the page declaration is left, and the rest are clear: <% @ Page Language = " C # " Autoeventwireup = " True " Codefile = " Ajax_getusername.aspx.cs " Inherits = " Ajax_getusername "   %>

Ajax_getusername.aspx.cs page write processing logic: 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) client requests

<% @ 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 () {< br> 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 >

Example 2: Request XML document
1) Create 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) client requests
Function btngetxmlclickhandler () {< br> var req = New sys. net. webrequest ();
req. set_url ( " userinfos. " );
req. add_completed (getxmlcompleted);
req. invoke ();
}
Function getxmlcompleted (Executor, eventargs) {
If (Executor. get_statuscode () =   200 ) {
Alert (Executor. get_xml (). XML );
}
}