About .NET Timer and COM object problem...

[zishen]

Hello, recently I came across a strange problem with my app. I utilities
interop to
make DirectShow into .NET. When I use it in single thread, it works fine.
But when
I use System.Threading.Timer to trigger some actions with DirectShow, there
will
occur some InvalidCastExceptions at QueryInterface(). However, I change
timer to
System.Windows.Form.Timer, this problem disappears. Anyone got this problem
before? And anyone who knows why it happens?Thanks~~