How do I throw an exception in VB?

[Erik Johnson]

I am trying to implement some structured exception handling (VC++ background). How do I throw an exception in VB?

Thanks in advance
Erik Johnson

Erik Johnson

[Weasel]

They're called events in VB I believe. Declare them at the top of the module that uses them and call them with RaiseEvent.

Event foo()

Private Sub Command1_Click()
RaiseEvent foo
End Sub

Though when you think about it, how "structured" *is* the exception system? Return values for success or failure are more structured, exceptions are nothing but GOTOs.

[Erik Johnson]

Hmm... In VC++ you can throw an exception and pass back a strucure or an error class and have multiple handlers triggered on the type of class being returned. I am guessing that there is no equivelant in VB? Layering function error return types does not sound fun but I guess it's do-able.

Thanks for your help,
Erik


Erik Johnson

[BobClarke]

>> Return values for success or failure are more structured, exceptions are nothing but GOTOs

Do you mean this in a VB context, because exceptions are certainly more than that in some other languages (C++ and Java: stack is unwound and destructors are called without the programmer having to code anything)?

I'm not very familiar with VB or its exception handling abilities, so I'm just asking.

Weasel: No, I believe you can declare them with variables, but the *concept* of an exception is too haphazardly break from a *general location* exact point unknown to throw execution somewhere else entirely. Give it an arg list and it should work fine. And as opposed to passing structures, there's always that one other hated method of passing large and/or complex things. (But extremely useful) Global vars!