Error Handling Routine

  • Thread starter Thread starter dave h
  • Start date Start date
D

dave h

Hi,
In the code below, I created a small simulation of what is happening in a
larger context. Of course this is bad code, but I wanted to force an error
to get at the error handling problem. If I run this code without my error
handler (comment out the On Error Goto...) then Access returns a message box
for a runtime error of 91 and its description. With my error handling
enabled, my message box returns an error of 0 and no description. This is
the same behavior I get in my actual project. What am I doing wrong?
Thanks, Dave H.

Private Sub btnTest1_Click()
On Error GoTo Error_Handler

Dim rst As Recordset 'force an error
Forms("frmTest1").Controls("txtTest1") = rst.Fields("xx")

Exit_Procedure:
Exit Sub
Error_Handler:
On Error Resume Next
MsgBox "error Number " & Err.Number & ", " & Err.Description,
Buttons:=vbCritical
Resume Exit_Procedure
End Sub
 
Get rid of the On Error Resume Next, or put it after the Msgbox; it's
clearing the error number before you get a chance to use it.
 
Thanks Mark,
Kind of annoying however, as I took that error handling routine from the
WROX book Access 2003 VBA and they clearly use the On Error Resume Next and
then use a msgbox to display err.number and err.description. Sure glad you
guys are around. Dave H.
 
Sussman and Smith are too good to have done that!

Reread your book slowly and carefully. Check the context of what they are
doing.
 
I didn't mean to sound like I was passing judgement on the experts - because
I'm definitely an Access novice. And, the book is generally quite helpful.
BTW, this one is written by some other folks Cardoza, Hennig, Seach &
Stein - who also seem to be very competent. So, clearly I could be
misintrepeting something about the context - but I'm having trouble seeing
what that is. And this is not about beating an issue to death - I'm still
wondering if I'm missing some important point as I try to develop a good
error handling model that I can use over and over. If someone has some
insight, the book again is WROX Access 2003 VBA Programmer's Reference and
their final error handling model is on page 277. I have no doubt that I
could be misunderstanding how the Err.number display yields a valid result
when it comes shortly after the "On Error Resume Next". The only 2 lines of
code between the two are:
DoCmd.SetWarnings True
DoCmd.Hourglass False
Which they describe as cleanup items and should not restore a previously
cleared error code. They mention that the "On Error Resume Next", which is
the first line of "Error_Handler:" is used for "This overrides the normal
error handling and forces the code to contineue even if an error is
encountered".

Any insight will be appreciated. Thanks, Dave H
 
dave said:
In the code below, I created a small simulation of what is happening in a
larger context. Of course this is bad code, but I wanted to force an error
to get at the error handling problem. If I run this code without my error
handler (comment out the On Error Goto...) then Access returns a message box
for a runtime error of 91 and its description. With my error handling
enabled, my message box returns an error of 0 and no description. This is
the same behavior I get in my actual project. What am I doing wrong?
Thanks, Dave H.

Private Sub btnTest1_Click()
On Error GoTo Error_Handler

Dim rst As Recordset 'force an error
Forms("frmTest1").Controls("txtTest1") = rst.Fields("xx")

Exit_Procedure:
Exit Sub
Error_Handler:
On Error Resume Next
MsgBox "error Number " & Err.Number & ", " & Err.Description,
Buttons:=vbCritical
Resume Exit_Procedure
End Sub
Click to expand...


The first thing you should do in the error handler code is
save the error number in a variable. There are too many
ways for the number to be reset (On Error) or vhanges (any
other error) for you to trust it after the handler does much
of anything.
 
Dave,

I just stumbled across this thread. I don't know who wrote that bit, but I
agree that it's pretty silly thing to do.

Regards,
Graham R Seach
Microsoft Access MVP
Sydney, Australia
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