Strange Message about threads in C#

Question

Hello,

I have a program that I run and in the middle I get this message:

Managed Debugging Assistant 'ContextSwitchDeadlock' has detected a problem in 'C:\Documents and Settings\Lena G\My Documents\SchoolStuff\IR Information\Home Work\FianlProject\finalProject\finalProject\bin\Debug\finalProject.vshost.exe'. Additional Information: The CLR has been unable to transition from COM context 0x3407968 to COM context 0x3407ad8 for 60 seconds. The thread that owns the destination context/apartment is most likely either doing a non pumping wait or processing a very long running operation without pumping Windows messages. This situation generally has a negative performance impact and may even lead to the application becoming non responsive or memory usage accumulating continually over time. To avoid this problem, all single threaded apartment (STA) threads should use pumping wait primitives (such as CoWaitForMultipleHandles) and routinely pump messages during long running operations.

I understand that it has something to do with the fact that it runs for 60 seconds without stopping or something like that? How is it a problem? I also put [STAThread] before the main of my program because if I remove it then it shows me this message:

An unhandled exception of type 'System.Threading.ThreadStateException' occurred in System.Windows.Forms.dll Additional information: Current thread must be set to single thread apartment (STA) mode before OLE calls can be made. Ensure that your Main function has STAThreadAttribute marked on it. This exception is only raised if a debugger is attached to the process.

Anyone know how I can solve this problem?

Thanks in advance,

Lena

Answer 1

You need to make sure that your thread that owns the COM component isn't being "locked up" via processing for >60 seconds.

What's probably happening is that you have a COM object in a form, and you're doing work on the UI thread. If your UI gets blocked by the processing for >60 seconds, the COM component can complain.

Consider using a BackgroundWorker instance to handle your long running process. This would push the work onto a background thread, and allow the COM component to process messages without complaints.

Answer 2

It is a warning that's generated when you make calls on an ActiveX object from a background thread and your main thread is blocked. Perhaps more likely: there was a bug in the retail version of Visual Studio 2005 that tripped this warning for no good reason. It got fixed in Service Pack 1, be sure you have that installed. Yet another workaround is to shut it up. Debug + Exceptions, Managed Debugging Assistants, untick the ContextSwitchDeadlock warning. But use SP1 if you don't have it.