MSDN的例子有错误，接口方法已改变。给个例子
<% @ Page Language = " C# "  EnableViewState = " false " %>

<% @ Implements Interface = " System.Web.UI.ICallbackEventHandler "   %>
<! DOCTYPE html PUBLIC  " -//W3C//DTD XHTML 1.0 Transitional//EN "   " http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd " >

< script runat = " server " >
    
     public   int  cbCount  =   0 ;
    StringBuilder sb  =   new  StringBuilder( " No page postbacks have occurred. " );
     //  Define method that processes the callbacks on server.
     public   void  RaiseCallbackEvent(String eventArgument)
    {
        cbCount  =  Convert.ToInt32(eventArgument)  +   1 ;
        
    }

     //  Define method that returns callback result.
     public   string  GetCallbackResult()
    {
         return  cbCount.ToString();
    }

     protected   void  Page_Load( object  sender, EventArgs e)
    {
        

         //  Check if this is a postback.
         if  (Page.IsPostBack)
        {
            sb.Append( " A page postback has occurred. " );
        }

         //  Write out any messages.
        MyLabel.Text  =  sb.ToString();

         //  Get a ClientScriptManager reference from the Page class.
        ClientScriptManager cs  =  Page.ClientScript;

         //  Define one of the callback script's context.
         //  The callback script will be defined in a script block on the page.
        StringBuilder context1  =   new  StringBuilder();
        context1.Append( " function ReceiveServerData1(arg, context) " );
        context1.Append( " { " );
        context1.Append( " Message1.innerText =  arg; " );
        context1.Append( " value1 = arg; " );
        context1.Append( " } " );

         //  Define callback references.
        String cbReference1  =  cs.GetCallbackEventReference( this ,  " arg " ,
             " ReceiveServerData1 " , context1.ToString());
        String cbReference2  =  cs.GetCallbackEventReference( " ' "   +
            Page.UniqueID  +   " ' " ,  " arg " ,  " ReceiveServerData2 " ,  "" ,
             " ProcessCallBackError " ,  false );
        String callbackScript1  =   " function CallTheServer1(arg, context) { "   +
            cbReference1  +   " ; } " ;
        String callbackScript2  =   " function CallTheServer2(arg, context) { "   +
            cbReference2  +   " ; } " ;

         //  Register script blocks will perform call to the server.
        cs.RegisterClientScriptBlock( this .GetType(),  " CallTheServer1 " ,
            callbackScript1,  true );
        cs.RegisterClientScriptBlock( this .GetType(),  " CallTheServer2 " ,
            callbackScript2,  true );

    }
</ script >

< script type = " text/javascript " >
var value1  =   0 ;
var value2  =   0 ;
function ReceiveServerData2(arg, context)
{
    Message2.innerText  =  arg;
    value2  =  arg;
}
function ProcessCallBackError(arg, context)
{
    Message2.innerText  =   ' An error has occurred. ' ;
    
}
</ script >

< html xmlns = " http://www.w3.org/1999/xhtml " >
< head id = " Head1 "  runat = " server " >
     < title > ClientScriptManager Example </ title >
</ head >
< body >
     < form id = " Form1 "  runat = " server " >
         < div >
            Callback  1  result:  < span id = " Message1 " > 0 </ span >
             < br  />
            Callback  2  result:  < span id = " Message2 " > 0 </ span >
             < br  />
             < br  />
             < input type = " button "  value = " ClientCallBack1 "  onclick = " CallTheServer1(value1, alert('Increment value')) "   />
             < input type = " button "  value = " ClientCallBack2 "  onclick = " CallTheServer2(value2, alert('Increment value')) "   />
             < asp:Button ID = " Button1 "  runat = " server "  Text = " Button "   />
             < br  />
             < br  />
             < asp:Label ID = " MyLabel "  runat = " server "  EnableViewState = " true " ></ asp:Label >
         </ div >
     </ form >
</ body >
</ html >