WD97: Converted WordBasic On Error Statements May Fail (177271)

CAUSE

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By design, the On Error statement in Visual Basic works differently from WordBasic. In Visual Basic, On Error is not cleared when an error occurs, while in WordBasic, the On Error statement is cleared, the error trap is reset, and your code continues to run.

Therefore, the following sample converted WordBasic code fails when an error occurs the second time.

   Sub Main()
      ' Clear error trap. Set error trap.
      On Error GoTo -1: On Error GoTo ErrorTrap
      ' Loop 10 times.
      For i = 1 To 10
         ' Artificially raise an error.
         Err.Raise 5
   ErrorTrap:
        ' Decision tree based on error returned.
        If Err.Number = 0 Then
            ' If no error occurred, do this...
            count_ = count_ + 1
        Else
            ' Else, if error occurred, do this...
            Err.Number = 0
        End If
      Next
   End Sub

RESOLUTION

To resolve this issue, make the On Error statement the first statement inside the loop.

   Sub Main()
      ' Loop 10 times.
      For i = 1 To 10
      ' Clear error trap. Set error trap.
      On Error GoTo -1: On Error GoTo ErrorTrap
         ' Artificially raise an error.
         Err.Raise 5
   ErrorTrap:
        ' Decision tree based on error returned.
        If Err.Number = 0 Then
            ' If no error occurred, do this...
            count_ = count_ + 1
        Else
            ' Else if error occurred, do this...
            Err.Number = 0
        End If
      Next
   End Sub

In this example, the Err.Raise statement artificially raises an error for demonstration purposes. When the error occurs and the next iteration of the loop occurs, the "On Error GoTo -1" statement clears the error trap and the "On Error GoTo ErrorTrap" statement resets the error trap. The loop continues to process without interruption until it completes the designated number of iterations (10).

REFERENCES

For more information about the On Error Statement, click the Office Assistant in the Visual Basic Editor, type On Error, click Search, and then click to view "On Error Statement."

NOTE: If the Assistant is hidden, click the Office Assistant button on the Standard toolbar. If Word Help is not installed on your computer, please see the following article in the Microsoft Knowledge Base:

120802 Office: How to Add/Remove a Single Office Program or Component

For more information about getting help with Visual Basic for Applications, please see the following article in the Microsoft Knowledge Base:

163435 VBA: Programming Resources for Visual Basic for Applications

WD97: Converted WordBasic On Error Statements May Fail (177271)

SYMPTOMS

CAUSE

RESOLUTION

STATUS

REFERENCES