Question

I would like to create an object of a VB6 class and call a method on that object. If an error occurs in

that method I would like to be able to raise an error in the method and catch it outside the class, in the

routine which I called the method.

The class for example may contain:

Const cmlngMYERROR As Long = vbObjectError + 1001

Public Sub MyMethod()

    ...

    Err.Raise cmlngMYERROR, Err.Source, Err.Description

End Sub

The calling routine may contain:

Private Sub MyCallingRoutine()

    Dim objMyObject As ClassName

On Error GoTo ErrorHandler

    Set objMyObject = New ClassName

    objMyObject.MyMethod

    Exit Sub

ErrorHandler:
    If Err.Number=clngMYERROR Then
        ...
    End If

End Sub

The problem I have is that you cannot define public constants at the top of a class. Therefore, you cannot

check the error number using the defined constant in the calling routines error handler. What is the best

practise to check the error code in the calling routine? Am I using error handling correctly in this

example (or on the right track at least)?

Thanks in advance.

Answer 1

There is a clever (ugly?) trick to emulate a public constant: use a public Enum instead

Public Enum PseudoConst
  cmlngMYERROR = vbObjectError + 1001     
End Enum