Default Exception Value

[bh]

Is there such thing as a default exception value? I'm trying to pass an
optional parameter, containing an exception back to a calling procedure. In
the pseudocode, below, what might I put in place of the ??? in the calling
procedure & corresponding function? Thanks in advance. BH

CALLING PROCEDURE:
Dim ex as exception
ex = ???
GetPossibleException(ex)


Public Function GetPossibleException(optional ByRef ex as exception = ???)
as datareader
Try
..
..
..
Return MyDataReader

Catch MyExc as Exception
ex = MyExc
End Try

 

[Herfried K. Wagner [MVP]]

Is there such thing as a default exception value? I'm trying to pass an
optional parameter, containing an exception back to a calling procedure.
In the pseudocode, below, what might I put in place of the ??? in the
calling procedure & corresponding function? Thanks in advance. BH

CALLING PROCEDURE:
Dim ex as exception
ex = ???
GetPossibleException(ex)


Public Function GetPossibleException(optional ByRef ex as exception = ???)

This won't work because 'Exception' is a reference type and specifying a
custom default value when using 'Optional' only works for certain value
types and strings. You may want to use overloading instead.

 

[Jay B. Harlow]

bh,
In addition to the other comments.

There is only one available default value for reference types other then
String. Nothing. literally.

Public Function GetPossibleException(optional ByRef ex as exception =
Nothing) as datareader

If you want a default other then Nothing, then consider overloading as
Herfried suggests:


Public Function GetPossibleException() as datareader
Return GetPossibleException(New Exception())
End Function

Public Function GetPossibleException(ByRef ex as exception) as datareader

HOWEVER! Why would you pass a default to a ByRef parameter that you are
returning a value to?