Web Services (ASMX 1.1) Performance Guidelines - COM Interop
From Guidance Share
- J.D. Meier, Srinath Vasireddy, Ashish Babbar, and Alex Mackman
[edit]
Avoid calling single-threaded apartment objects.
Calling single-threaded apartment (STA) objects from Web services is neither tested nor supported. The ASPCOMPAT attribute that you would normally use in ASP.NET pages when calling Apartment threaded objects is not supported in Web services.
References
For more information, see Microsoft Knowledge Base article 303375, "INFO: XML Web Services and Apartment Objects," at http://support.microsoft.com/default.aspx?scid=kb;en-us;303375.