COM object that has been separated from its underlying RCW cannot be used.

Question

hi, I am trying to use the OpcRcw.da.dll; If I interop this dll inside a test console project everything works. But if I build dll project to do my interop gymnastic and ref my library into my console project I am getting this error.

COM object that has been separated from its underlying RCW cannot be used.

What need to be done to a class lib project to not kill the RCW ref....

thanks

Answer 1

It's somewhat hard to tell what your actual application is doing, but it sounds like you may be instantiating the COM object and then attempting to access it from another thread, perhaps in a Timer.Elapsed event. If your application is multithreaded, you need to instantiate the COM object within each thread you will be using it in.