I'm not the most
experienced with doing this sort of thing with RadAjax, but would it be possible to set a flag on OnRequestStart
and then clean it on OnResponseEnd
? This way, all you'd ever need to do is check for that flag being raised and you'll know you're in the middle of an async request.
Not sure how well that would work with WatiN, but in looking at the RadAjax client-side members I cannot find an equivelant to IsInAsyncPostback... but then again, since RadControls are built on top of MS Ajax, wouldn't you still have access to the page commands that pushp is referring to?