CROSS Page Posting in ASP.NET

Postback and Cross Page Posting

If(Page.IsPostBack==true)                      

Ispostback->

When the page is loaded for the first time it is false, when the page is loaded again then it is true.

Example

If (Ispostback) ->

If true then it goes inside that loop

If (! ispostback) ->

If false then it goes inside that loop. We write this line in page load in most of the application.

Cross Page PostBack  is which is  used to submit one Page(Default.aspx) controls to another page(Default2.aspx) and access Default.aspx control values in Another Page(Default2.aspx)

 Example

Cross page posting is submitting the form to a different page. This is usually required when you are creating a multi-page form to collect information from the user on each page. When moving from the source to the target page, the values of controls in the source page can be accessed in the target page.

Design the Form as

Default2.aspx

Default2.aspx.cs

Go to Default3.aspx

Default3.aspx.cs

Difference between Server. Transfer and Cross Page Posting

In ‘Server.Transfer’, the URL doesn't change whereas in cross page posting, the form is submitted to a different page, thereby changing the url.

The Server.Transfer method is a server-based operation whereas cross-page postback is a client-based transfer.

By using Master Page

ContentPlaceHolder pageContent =

(ContentPlaceHolder)

(Page.PreviousPage.Form.FindControl ("Content1"));

TextBox1.Text = pageContent.FindControl("button1");

To avoid casting the control type, you can also access the previous page data(Default2.aspx) by creating public properties that expose the data that you need to access.

In Default2.aspx

public String BTarget

{

        get

        {

             return button1.Text;

        }

}

In the ‘Default3.aspx’, access the value of the Button using the exposed property

Label1.Text = PreviousPage.BTarget;