You learn something new everyday...
Try [ tryStatements ] [ Catch [ exception [ As type ] ] [ When expression ] [ catchStatements ] ] [ Exit Try ] ... [ Finally [ finallyStatements ] ] End Try
Optional. A Catch statement with a When clause will only catch exceptions when expression evaluates to True. A When clause is only applied after checking the type of the exception, and expression may refer to the identifier representing the exception.
I never did! I can't think of a good use for it right at this moment, but I'm still shocked that I never noticed it before... now what to do with it?