微软认为这是VS2008的一个bug，并且将在VS2010的Beta2中解决。。。
你如果非要调试，就用别的协议吧。。
以下摘自微软网站声明：http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=472536
If you expose a WCF web service via both WSDualHttpBinding and the newer Silverlight PollingDuplexBinding, and then make a simplex call to the web service over the WSDualHttpBinding while debugging the Visual Studio solution, Visual Studio will respond with the error message "Unable to automatically debug 'servicename'. The remote procedure could not be debugged. This usually indicates that debugging has not been enabled on the server. See help for more information."
你如果非要调试，就用别的协议吧。。
以下摘自微软网站声明：http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=472536
If you expose a WCF web service via both WSDualHttpBinding and the newer Silverlight PollingDuplexBinding, and then make a simplex call to the web service over the WSDualHttpBinding while debugging the Visual Studio solution, Visual Studio will respond with the error message "Unable to automatically debug 'servicename'. The remote procedure could not be debugged. This usually indicates that debugging has not been enabled on the server. See help for more information."
建议
Product Language
English
Version
Visual Studio 2008 SP1
Operating System
Windows Vista
Operating System Language
English
Steps to Reproduce
(1) Create a web service which includes both duplex and standard simplex methods.
(2) Expose that web service via both the WSDualHttpBinding and the PollingDuplexBinding.
(3) Make a simplex (non-duplex) call to the web service over the WSDualHttpBinding.
(2) Expose that web service via both the WSDualHttpBinding and the PollingDuplexBinding.
(3) Make a simplex (non-duplex) call to the web service over the WSDualHttpBinding.
Actual Results
An error dialog box that says, "Unable to automatically debug 'servicename'."
Expected Results
The ability to debug the web service in question.
TAP Code (if applicable)