ModalPopupExtender .Show() Caveat

I’ll admit it… I don’t mind AJAX.NET.  In fact, I like a lot of the toolkit controls they provide.  Because I am “chained” to .NET and DotNetNuke, I don’t much of a choice when it comes to bleeding-edge technology.

One thing I tend to use frequently is the ModalPopupExtender.  I had a requirement to show the modal popup when the page loads.  Easy enough, I just instansiate the code and in the onLoad code-behind do mpe.Show().

However, this didn’t work It gave me an ugly error.  After sifting through a bunch of unhelpful forum posts online, I came across this issue in the AJAX Control Toolkit issue tracker.  Reading through the description, you notice that the problem has to do with the fact that there is a missing semi-colon if you try to invoke the modal through server-side on a page with validation.

Because the modal I was programming would not need the validation on the page, I simply turned off validation when the modal was invoked.  This worked like a charm.  If you require validation with the modal, I strongly suggest you check out the issue tracker page.