先看MSDN Library 2005上的这个例子！
------ ClientCallback.aspx ------
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ClientCallback.aspx.cs" Inherits="ClientCallback" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/ xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtm l" >
<head id="Head1" runat="server">
<title>Callback Test</title>
<script type="text/javascript">
function ReceiveServerData(receivedStr, context)
{
alert(receivedStr);
}
</script>
</head>
<body>
<form id="form1" runat="server">
<input type="button" value="Callback" onclick="CallServer(''argument'', ''context'')"/><br />
</form>
</body>
</html>-------- ClientCallbacp.aspx.cs -----------
// ClientCallback.aspx.cs
using System;
using System.Data;
using System.Configuration;
using System.Collections;
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;
public partial class ClientCallback : System.Web.UI.Page, System.Web.UI.ICallbackEventHandle r
{
void Page_Load(object sender, EventArgs e)
{
ClientScriptManager cm = Page.ClientScript;
String cbReference = cm.GetCallbackEventReference(this, "arg", "ReceiveServerData", "");
String callbackScript = "function CallServer(arg, context) {" + cbReference + "; }";
cm.RegisterClientScriptBlock(this. GetType(), "CallServer", callbackScript, true);
}
private string returnStr;
//function called by client, executed on server
public void RaiseCallbackEvent(String eventArgument)
{
//do something with return argument
returnStr = eventArgument.ToUpper();
return;
}
//function that sends result?
public string GetCallbackResult()
{
&nbs