Exception getting past Application.ThreadException and AppDomain.CurrentDomain.UnhandledException

Question

I'm having a problem with an application hanging and giving me the default "Please tell Microsoft about this problem" popup, instead of the "unhandled exception" dialog in the application.

In the application code, the Application.ThreadException and AppDomain.CurrentDomain.UnhandledException are both redirected to a method which writes an error log to disk, saves a screenshot to disk, and shows a friendly dialog box.

But when this error occurs, none of those three things happen. All I get is this in the event viewer:

EventType clr20e3, P1 myapp.exe, P2 4.0.0.0, P3 47d794d4, P4 mscorlib, P5 2.0.0.0, P6 471ebc5b, P7 15e5, P8 27, P9 system.argumentoutofrange, P10 NIL

Given that the error only seems to happen after the application has been running for several hours, I wonder if it may be a memory-leak problem. I've searched a bit for "clr20e3" but only managed to find ASP.Net stuff. My application is Windows Forms (.Net 2.0) exe, using quite a few assemblies - in both C# and some unmanaged C++.

I guess that it could also be an error in the error handling method - As some answers suggest, I may try logging at the start of error handler (but given that that is pretty much what I do anyway...).

Any help solving this problem would be much appreciated - whether it is solutions, or suggestions in how to find out what the root cause of the problem is.

UPDATE: The root cause of the original bug was accessing an array with a negative index (that was the system.argumentoutofrange). Why this was not trapped is a bit of a mystery to me, but given than both exceptions were sent to the same handling code, I wonder if there may not have been a condition where (for example) both were invoked and fought over a resource (the log file, for example)?

I managed to prove this much by doing an EventLog.WriteEntry before anything else in the error handling code. Having now added a flag to prevent re-entry in the error handling, I no longer appear to have a problem...

Answer 1

Just shooting in the dark here - is it possible that the ArgumentOutOfRangeException is actually thrown from your exception handler?

Additionally, you didn't say what type of application is in question -- Application.ThreadException only affects WinForms threads, so if this isn't a GUI application it's useless. (See the remarks section in the MSDN documentation)

Answer 2

Have you checked whether the ArgumentOutOfRangeException is thrown from your handler itself? May be worthwhile doing a simple write to the event log or trace at the entry of your exception handler and confirm you're actually hitting it.

Edit: Information to writing to the event log can be found at:

http://support.microsoft.com/kb/307024