MS-Access, VBA and error handling

Question

This is more an observation than a real question: MS-Access (and VBA in general) is desperately missing a tool where error handling code can be generated automatically, and where the line number can be displayed when an error occurs. Did you find a solution? What is it? I just realized how many hundreds of hours I spared since I found the right answer to this basic problem a few years ago, and I'd like to see what are your ideas and solutions on this very important issue.

Answer 1

Well there are a couple of tools that will do what you ask MZ Tools and FMS Inc come to mind.

Basically they involve adding an:

On Error GoTo ErrorHandler

to the top of each proc and at the end they put an:

ErrorHandler:
  Call MyErrorhandler Err.Number, Err.Description, Err.LineNumber

label with usually a call to a global error handler where you can display and log custom error messages

Answer 2

My solution is the following:

1. install MZ-Tools, a very interesting add-on for VBA. No they did not pay me, anyway it is free.
2. program a standard error handler code such as this one (see MZ tools menu/Options/Error handler):

---

On Error GoTo {PROCEDURE_NAME}_Error
{PROCEDURE_BODY}
On Error GoTo 0
Exit {PROCEDURE_TYPE}

{PROCEDURE_NAME}_Error:
debug.print "#" & Err.Number, Err.description, "l#" & erl, "{PROCEDURE_NAME}", "{MODULE_NAME}"

---

This standard error code can be then automatically added to all of your procs and function by clicking on the corresponding button in the MZ-Tools menu. You'll notice that we refer here to an undocumented value/property of VBA (2003 edition), 'erl', which stands for 'error line'. You got it! If you ask MZ-Tools to automatically number your lines of code, 'erl' will then give you the number of the line where the error occured. You will have a complete description of the error in your immediate window, such as:

#91, Object variable or With block variable not set, l# 30, addNewField, Utilities

Of course, once you realize the interest of the system, you can think of a more sophisticated error handler, that will not only display the data in the debug window but will also:

1. display it as a message on the screen
2. Automatically insert a line in an error log file with the description of the error or
3. if you are working with Access or if you are connected to a database, automatically add a record to a Tbl_Error table!

meaning that each error generated at the user level can be stored either in a file or a table, somewhere on the machine or the network. Are we talking about building an automated error reporting system working with VBA?

Answer 3

What about using "Erl", it will display the last label before the error (e.g., 10, 20, or 30)?

Private Sub mySUB()
On Error GoTo Err_mySUB
10:
    Dim stDocName As String
    Dim stLinkCriteria As String
20:
    stDocName = "MyDoc"
30:
    DoCmd.openform stDocName, acFormDS, , stLinkCriteria    
Exit_mySUB:
    Exit Sub
Err_mySUB:
    MsgBox Err.Number & ": " & Err.Description & " (" & Erl & ")"
    Resume Exit_mySUB
End Sub