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What is the difference between PostBack & Callback? Please give sample code?

24 New Member

What is the difference between PostBack and Callback ( !IsPostBack and if(!IsCallback) )

Like in the following Code Snippet:
Expand|Select|Wrap|Line Numbers
  1.         protected void Page_Load(object sender, EventArgs e)
  2.         {           
  3.             if (!IsPostBack)
  4.             {
  6.             }
  8.             if(!IsCallback)
  9.             {
  11.             }
  12.         }

As far as I know, when I 1) refresh the page or 2) revert back to the page after round trip, the behavior is such that IsPostBack = !IsCallback. I don't find any difference.

Can you please explain with example code?

Just want a sample code (for Page_Load event) that will demonstrate the difference in the Page_Load event so that I can toggle breakpoint and understand it for myself.

Oct 24 '09 #1
2 4108
750 Recognized Expert Contributor
A Postback occurs when the data (the whole page) on the page is posted from the client to the server.During a page postback, the Web page and controls are recreated and a new version of the entire Web page is rendered on the client.

Callback is also a special kind of postback, but it is just a quick round-trip to the server to get a small set of data.

Determine How ASP.NET Web Pages Were Invoked
Oct 27 '09 #2
24 New Member
Thanks for the reply!
Nov 3 '09 #3

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