C# App: Detecting Process.Exited causes violation

[mspace]

I'm fairly new to .NET programming, so bear with me a bit.

The application I'm developing implements a 'toolbar' type pull-down window that lists the applications that have been launched by the user (through my GUI). My current issue is with the detection of one of those processes exiting. When the user closes the application, I need to remove the menu item from my pull-down.

In order to accomplish this, I declare an event handler:
p.Exited += new System.EventHandler(this.processExited);

This works, but when I run the application in debug mode, Visual Studio gives me an 'InvalidOperation' exception stating that cross-thread operation is not valid when I exit the other app. I thought this was the purpose of using the event. Am I missing something basic? Would make a difference if the handler method was static?

Thanks,
Mike

[Plater]

If you look up the error on MSDN you see they offer some workarounds for that.
They have a background worker and a delegate that calls NeedsInvoke or something.
If you play around with that you might find something that removes the "Exception".

[mspace]

Thanks for the response - I was unable to find anything useful. I keep coming back to the thought that I shouldn't need a workaround...
A process wouldn't detect if itself had ended, so by the nature of this event, another process is going to react to it. Why would it be causing an exception? Has anyone else had experience using this event?

I noticed in the sample code on MSDN that they never explicitly declare an EventHandler. Is that oversight, or would that be by design?

Mike

[Plater]

I usually run into this error when I have multiple threads on my own application.
(I like to have a textbox on the main window that gets updates from the other threads and that throws the same exception)

Do you have anything like that? A System.Threading.Timer or System.Threading.Thread running that might be trying to talk to something?

[mspace]

I have a few other threads that run other forms (OSK type things), but they are not involved in this issue.
The basic function is that I launch a process from my main form, retain the handle and display the title in a pull-down menu, then try to remove the title from the pull-down when the process exits.

I tried a few other things - it appears to only complain when I access controls on my form. Is it possible that windows runs this event handler in a thread by itself?

[Plater]

If it did, that would explain it.

Its really only a best practices type exception.
It's letting you know that what you're doing isn't garunteed to happen in the correct order and might go in to re-entry ( in the middle of say appending text to a textbox, another thread start doing it and one overwrites the other)

[mspace]

OK - thanks again for your help. I guess I will just ignore the exception and get back to work...