How do I distinguish between AJAX postback and regular postback?

I just installed Ajax 1.0 with VS2005 SP1 and am trying to add AJAX to an existing site.

However, the site right now has fairly complex code in the master page defined in Page_init, Page_load, and PreRender events. I'd really like to skip those calls if it is an AJAX post back. I looked at the Page class and found IsCallBack and IsPostBack, both of which will not be triggered by an AJAX post back.

I thought of using a hidden variable (something like AJAXCall) and using a Javascript to set a value with every control that can trigger an AJAX postback, but that seems like not the right way to do it.

Does anyone know how to tell the difference between the two, or is it possible to skip Page_init, Page_load, and PreRender events with an AJAX call?

Thanks,

Ming

Yes you can, but you have to use UpdatePanel.

Girijesh:

Yes you can, but you have to use UpdatePanel.

I have tried the following setups with no success. In the master page, I included my script manager. Then I had an update panel with a button which updates a label with the system time. This takes about 10 seconds to update. The debugger tells me it executes Page_Load, Page_Init and PreRender.

Then I tried to include an update panel with a button inside page that inherits the master page, it also goes into all 3 methods. I tried this with my existing website, as well as a brand new AJAX enabled website.

Any ideas?

Thanks,

Ming

Hi Ming,
You can use ScriptManager.IsInAsyncPostBack property to distinguish them.
Hope this helps.

Raymond Wen - MSFT:

Hi Ming,
You can use ScriptManager.IsInAsyncPostBack property to distinguish them.
Hope this helps.

It worked like a charm. Thanks for telling me exactly what I was looking for.

Thanks!