问题
I have a silverlight app that uses WCF both by polling Duplex and "normal" async calls. everything was working fine, until I added a global.asax file.
After an hour of googling, I came across this rather dated blog by Jean-Dirk Stuart that suggested commenting out the stubbed Session_start event.
Sure enough that corrected the problem, but it raises a concern. Why would this seemly benign member of the global.asax file break the wcf calls.
回答1:
Yeah, this is a little known but annoying issue. The problem comes down to session state being enabled once you add a global.asax file to your web project. Once session state is enabled, the server will only execute the calls sequentially. Here are two articles with some more in-depth information:
http://blogs.msdn.com/b/silverlightws/archive/2009/09/30/having-a-pollingduplex-service-and-any-other-wcf-service-in-the-same-website-causes-silverlight-calls-to-be-slow.aspx
http://weblogs.asp.net/olakarlsson/archive/2010/05/20/simultaneously-calling-multiple-methods-on-a-wcf-service-from-silverlight.aspx
This behaviour only occurs when using the browser networking stack, so your options are:
- Disable session state in your web project, or
- Use the client networking stack
Hope this helps...
Chris
回答2:
There are some types of binding which support accessing asp.net session data, I really dont see how it would affect unless WCF tries to hook into the session_start event just like a http module does. You could also use reflector to disassemble the code where you where getting the exception.
来源：https://stackoverflow.com/questions/4412124/how-can-a-newly-added-global-asax-file-make-a-mess-of-my-wcf-service