Rick
Sun May 02 09:22:42 CDT 2004
I remember having trouble getting my head completely around this error
object propagation problem back when I first devised my err.raise
solution (some 3 or 4 years ago now) and I wasn't necessarily 100% sure
of it back then. In the mean time, you are the first to raise a concern
about how it will operate since then. Just so I can be sure I understand
the problem fully, can you give me an example piece of code that
demonstrates where my code doesn't work as you think it should, but
where your proposed change does... that would help me out greatly.
Thanks.
Rick - MVP
"Pásztor, Zoltán" <pasztor@ml-cons.hu> wrote in message
news:OoMPwsEMEHA.1340@TK2MSFTNGP12.phx.gbl...
> Rick,
>
> your workaround isn't quite correct, I'm afraid.
>
> Calling the modified IsArrayBounded function will always raise an
error, and
> if the call is made from inside an error handler, then it is going
upward
> the error chain.
>
> In general, I save the Err object at the begining of any handler if
there is
> any chance that the handler's code is going to change it (including
> clearing), and use the saved info for whatever it's needed.
>
> But I think the desired effect can be achieved if instead of raising
the
> error, you just restore the saved items (except of course the
LastDllError),
> as in:
>
> Function IsArrayBounded(ArrayIn As Variant) As Boolean
> Dim iErrN As Long
> Dim ErrObj As Variant
>
> iErrN = Err.Number
> If iErrN Then
> 'Store Global Err Object
> ErrObj = Array(Err.Source, Err.Description, _
> Err.HelpFile, Err.HelpContext)
> End If
>
> On Error Resume Next
> IsArrayBounded = (UBound(ArrayIn) >= LBound(ArrayIn))
>
> If iErrN Then
> 'Restore Global Err Object
> With Err
> .Number = iErrN: .Source = ErrObj(0): .Description = ErrObj(1)
> .HelpFile = ErrObj(2): .HelpContext = ErrObj(3)
> End With
> End If
> End Function
>
> --
> PZ
> Rick Rothstein wrote:
> > You shouldn't think of "errors" as being something bad; rather think
> > of it as information in another format. There is nothing wrong with
> > trapping errors and reacting to them, nothing at all.
> >
> > I've posted this in the past...
> >
> > Function IsArrayBounded(ArrayIn As Variant) As Boolean
> > On Error Resume Next
> > IsArrayBounded = (UBound(ArrayIn) >= LBound(ArrayIn))
> > End Function
> >
> > which should work under the vast majority of your situations.
However,
> > someone once wrote in that the following construction could cause
> > unexpected behavior
> >
> >>> Sub SomeSub()
> >>> Dim myArray() As String
> >>> On Error GoTo ErrorTrap
> >>> Err.Raise 5
> >>> Exit Sub
> >>> ErrorTrap:
> >>> If IsArrayBounded(myArray) = False Then
> >>> 'Will not display "Invalid procedure call or argument",
> >>> 'but will instead display "Subscript out of range":
> >>> MsgBox "Error info: " & Err.Description
> >>> End If
> >>> End Sub
> >
> > Now, I don't use this type of construction myself; but, if you do,
the
> > following modification of my code should solve that problem
> >
> > Function IsArrayBounded(ArrayIn As Variant) As Boolean
> > Dim ErrObj As Variant
> > 'Store Global Err Object
> > ErrObj = Array(Err.Number, Err.Source, Err.Description, _
> > Err.HelpFile, Err.HelpContext)
> > On Error Resume Next
> > IsArrayBounded = (UBound(ArrayIn) >= LBound(ArrayIn))
> > 'Restore Global Err Object
> > Err.Raise ErrObj(0), ErrObj(1), ErrObj(2), ErrObj(3), ErrObj(4)
> > End Function
> >
> > Rick - MVP
> >
> >
> >
> > "dr. bandicoot" <anonymous@discussions.microsoft.com> wrote in
message
> > news:58E34BBC-4C36-4958-82FD-56AA668A96BF@microsoft.com...
> >> Is there any way to detect that an array has not been yet
dynamically
> > sized. If I run into LBound() before a Redim, I get subscript out of
> > range error and I want to eliminate this error (and I don't want to
do
> > error handling or any other "tricks"). Is there any legal keyword or
> > command like if array = nothing then etc... ???
> >>
> >> Thanks !
>
>