Step 1: Drag and Drop Script Manager Control


Step 2 :  Design Webform1.aspx like below


ajax5

Step 3 : Webform1.aspx.cs Code


using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace ServerCentricExample
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            TextBox1.Text = "1111";
            TextBox2.Text = "Naga";
            TextBox3.Text = "20000";
        }
    }
}

Step 4 :


♣    When we run the above application one request will go to the server for webform1.aspx. It is called as first request which is handling by server

♣    When user will click the display button second request will go to the server for the same web page from the same client which request is called as “ Post back request”, this post back request is also handling by server, because the above web page is following server centric programming model.