Silverlight PollingDuplex InnerChannel faulted with multipleMessagesPerPoll (serverPollTimeout)

Question

Im running silverlight client version 4.0.50917.0 and SDK version 4.0.50826.1

I\'ve created a simple silverlight client against a wcf pollingduplex binding:

Answer 1

I confirm the issue on a sample, with the same SDK and client versions.

The issue has some more implications on other browsers too: I am under the impression that MultipleMessagePerPoll doesn't seem to work correctly on them neither (Fiddler and Firebug show something which looks a lot like SingleMessagePerPoll)

However I could make it work by using the client Network stack (bypassing the browser network stack). This solution is however far from perfect, as cookies must be set manually in this case. It can can be annoying or a non-issue depending on your application.

To perform all http request through the client stack, use this before you start your service calls:

HttpWebRequest.RegisterPrefix("http://", WebRequestCreator.ClientHttp);

You could however be a little more specific, according to your needs.

If someone has a more satisfying answer, I would be glad to read it. If you are interested in reproducing the probleme, I have modified an old Tomek sample to use MultipleMessagePerPoll on SL4 instead of SingleMessagePerPoll on SL3.

Answer 2

This problem can be caused by adding global.asax to the hosting web site. Adding sessions to the hosting site apparently screws up the wcf polling duplex service. I struggled with this issue for several days and by merely deleting the global.asax file from the host web site the hang in the service went away. The multiplemessagesperpoll was a false lead. It works fine.

See this for more:

How can a newly added global.asax file make a mess of my WCF service