Mega Code Archive

 
Categories / ASP.Net Tutorial / Page Lifecycle
 

Server side call back (C#)

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs"  Inherits="RandomNumber" %> <!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 id="Head1" runat="server">     <title>Callback Page</title>          <script type="text/javascript">         function GetNumber(){                  UseCallback();         }                  function GetRandomNumberFromServer(TextBox1, context){                document.forms[0].TextBox1.value = TextBox1;         }     </script>      </head> <body>     <form id="form1" runat="server">     <div>         <input id="Button1"                 type="button"                 value="Get Random Number"                 onclick="GetNumber()" />         <br />         <asp:TextBox ID="TextBox1" Runat="server"></asp:TextBox>     </div>     </form> </body> </html> File: Default.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 RandomNumber : System.Web.UI.Page, System.Web.UI.ICallbackEventHandler {     private string _callbackResult = null;     protected void Page_Load(object sender, EventArgs e)     {         string cbReference = Page.ClientScript.GetCallbackEventReference(this,             "arg", "GetRandomNumberFromServer", "context");         string cbScript = "function UseCallback(arg, context)" +            "{" + cbReference + ";" + "}";         Page.ClientScript.RegisterClientScriptBlock(this.GetType(),            "UseCallback", cbScript, true);     }     public void RaiseCallbackEvent(string eventArg)     {         Random rnd = new Random();         _callbackResult = rnd.Next().ToString();     }     public string GetCallbackResult()     {         return _callbackResult;     } }