ASP.NET AJAX Tips and Tricks

By default ASP.NET AJAX will load and render your controls even if they do not need to be updated.
Example:



In this case the Panel marked as "Slow loading area" will be updated by default even on DropDownList1 selected index changed.

What can we do to prevent this?

You can set Panel1.Visible to true/false according to the current ajax request.

Example:



Enjoy!

PS: Running example can be found here.