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Why do I get "A first chance exception of type 'System.ArgumentException' occurred in mscorlib.dll" exception
Hi guy,
I'm a bit puzzled as to why I'm getting a "A first chance exception ..." when trying to remove an event handler using "RemoveHandler". I this particular case I have five (5) RemoveHandler statments looking identical, but with different parameters, and only the last statement fails.
The app appears to be working fine so I'm just a bit confused.
Any thoughts?
/Michael
I'm a bit puzzled as to why I'm getting a "A first chance exception ..." when trying to remove an event handler using "RemoveHandler". I this particular case I have five (5) RemoveHandler statments looking identical, but with different parameters, and only the last statement fails.
The app appears to be working fine so I'm just a bit confused.
Any thoughts?
/Michael
Bob Learned
There are too many possibilities to be sure of anything, without more detail.
ASKER
As part of creating a Form instance I added several event handlers that includes the following statement:
"AddHandler Me.ParentSection.Panel.Cli
Then as part of closing that Form I am removing the added event handlers amongst which is the following statement that compliments the AddHandler statement above:
"RemoveHandler Me.ParentSection.Panel.Cli
So I wasn't expecting any exceptions because stepping through the code I can't see any empty pointers, etc. so I'm a bit confused.
/Michael
"AddHandler Me.ParentSection.Panel.Cli
Then as part of closing that Form I am removing the added event handlers amongst which is the following statement that compliments the AddHandler statement above:
"RemoveHandler Me.ParentSection.Panel.Cli
So I wasn't expecting any exceptions because stepping through the code I can't see any empty pointers, etc. so I'm a bit confused.
/Michael
Michael,
Do you have the full stack trace text for the exception? When the form is closed, is it disposed?
Do you have the full stack trace text for the exception? When the form is closed, is it disposed?
ASKER
Sorry, I forgot to say that I get that message only in the IDE Immediate Window and not as a crash.
The Form also closes OK and all looks normal, except for those messages so I was just curious as to whether I should worry about that or not.
/Michael
The Form also closes OK and all looks normal, except for those messages so I was just curious as to whether I should worry about that or not.
/Michael
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ASKER
Actually I am using Try/Catch but (stupid me) I forgot to print the ex.Message from the "Catch ex As Exception", I only looked at the output in Immediate Window.
The message in (Catch ex As Exception) has the following message:
"Delegate to an instance method cannot have null 'This'."
That makes sense so, even though I expected all references to be valid, sometimes "Me.Sections.ParentForm' is Nothing and hence the failure.
Thanks for your assistance (as always).
/Michael
The message in (Catch ex As Exception) has the following message:
"Delegate to an instance method cannot have null 'This'."
That makes sense so, even though I expected all references to be valid, sometimes "Me.Sections.ParentForm' is Nothing and hence the failure.
Thanks for your assistance (as always).
/Michael