先看MSDN Library 2005上的这个例子！
------ ClientCallback.aspx ------
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ClientCallback.aspx.cs" ­ Inherits="ClientCallback" %>

   
       
       
   
       
         

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()
    {
        return returnStr;
    }
}
客户端用ReceiveServerData接收服务器返回的数据，

使用CallServer(’argument’, ’context’)传递数据到服务器。

客户端ok了，接下来是服务器端，
实现ICallbackEventHandle­ 接口，
private string returnStr;
 public void RaiseCallbackEvent(String eventArgument)   
    {
        returnStr = eventArgument.ToUpper();
        return;
    }
   
public string GetCallbackResult()
    {
        return returnStr;
    }

最后，将客户端方法和服务器端的方法关联起来，在Page_Load中实现，
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);

大功告成！

这种方法也能达到类似ajax的无刷新页面，而且实现起来十分简单。

http://pyw0818.cnblogs.com/archive/2006/05/30/413416.html