Asynchronous web service call returning null (called from ASP.NET asynchronous page)

Question

I am consuming a 3rd-party web service which has been implemented in WCF.

My consumer code resides on an ASP.NET asynchronous page.

Problem is, sometimes the BeginCallWebService() method is returning null. Shouldn't it always return an IAsyncResult object?

Should I ask the web service developer to modify their code, or is null a legit response?

Answer 1

Begin... should always return IAsyncResult as you'll need it to call End...

Currently his webservice implements async patterns (his bug), or your proxy provide it (your bug)?