Asp.net 2.0

.NET controls can be inserted into the other content page just like an into an ordinary page.

    <%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="AboutUs.aspx.cs" Inherits="About_Us" Title="Untitled Page" %>
   
  <asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
  </asp:Content>
  <asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder2" Runat="Server">
      
      
         <h3>About PIS</h3> 
      
      <p>
  </asp:Content>
  

Master Pages are really helpful in cases when you have a standard frame or backdrop layout for your site that has to repeated on every page of that site.

Create that once using a master page and use it on any number of pages as you want easily by refering to it as shown in the second code.

The Page.IsPostBack Property
It runs EVERY time the page is loaded
you can use the Page.IsPostBack property.
If you want to execute the code in the Page_Load subroutine only the FIRST time the page is loaded
If the Page.IsPostBack property is false, the page is loaded for the first time, if it is true, the page is posted back to the server

[COLOR=blue]Sub[/COLOR] Page_Load
    [COLOR=blue]If[/COLOR] [COLOR=blue]Not[/COLOR] IsPostBack
                 Validate()
    [COLOR=blue]End[/COLOR] [COLOR=blue]If[/COLOR]
[COLOR=blue]End[/COLOR] [COLOR=blue]Sub[/COLOR]

[COLOR=blue]private[/COLOR] [COLOR=blue]void[/COLOR] Page_Load()
{
    [COLOR=blue]if[/COLOR] (!IsPostBack)
    {
        Validate();
    }
}

Yes, IsPostBack helps to check that if the user has visited for the first time that is if it is a completely new session or the user is moving on the site or refreshing the page

what is the use of Autoeventwireup written in the first line of c sharp code.and by default it is true. ?

The ASP.NET page framework supports an automatic way to associate page events and methods.

If the AutoEventWireup attribute of the Page directive is set to true (or if it is missing, since by default it is true), the page framework calls page events automatically, specifically the Page_Init and Page_Load methods. In that case, no explicit Handles clause or delegate is needed.

But, in Visual Studio, if it is true, then the names of the methods must be as specified in its library otherwise it will not match and the events and methods will not be called.
As a consequence, you should always leave AutoEventWireup set to false when working in Visual Studio.

cooldudeietwhat is the use of Autoeventwireup written in the first line of c sharp code.and by default it is true. ?

The ASP.NET page framework also supports an automatic way to associate page events and methods.

The default value for AutoEventWireup is true for a C# web form, and false for a VB.NET web form.

When AutoEventWireup is true,
The ASP.NET runtime will automatically find and fire the method for the appropriate event. such as Page_Load() etc.
(the ASP.NET page framework can automatically raise events.)

If we switch to AutoEventWireup= false for a C# web form,
there is a little extra work to do. Somewhere we need to
explicitly wire up events.
(you must manually hook up events to event handlers)

Thanks @mahesh,@sarvesh 😀