BackgroundWorker can update control but not Show() Window?

[jstern81]

System:
Vista
Visual Studio 2005
C#

My goal is to check periodically for a certain condition which when
true indicates my system-tray application should make itself visible
to the user.

Problem: From my Timer, invoking the BackgroundWorker.RunWorkerAsync,
with an implemented RunWorkerCompleted method which calls Show() on
the application window, throws an InvalidOperationException: 'Cross-
thread operation not valid: Control accessed from a thread other than
the thread it was created on.'

I am able to successfully use the very same code to update a control
within the window, but I can't Show() the window to the user from the
Timer -> BackgroundWorker. Is this not possible with
BackgroundWorker? Should I be approaching this problem differently?
Any help is greatly appreciated.

[Glenn]

Controls can only be updated from the thread that created them. You
can allow this by setting CheckForIllegalCrossThreadCalls to false.
However, use this with caution as it may cause other problems.

...Glenn

[Andrew Badera]

Can't you pass a delegate and use invoke?

--
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--Andy Badera
http://higherefficiency.net
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(518) 641-1280
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[Glenn]

Can you?? I don't have any practical experience with delegates so I
wouldn't know.

When I get out of my specification phase and get back into my coding
phase, I'm going to look into delegates and see what I'm missing.

...Glenn