VBA enables an error-handling routine and can also be used to disable an error-handling routine. Without an On Error statement, any run-time error that occurs is fatal: an error message is displayed, and the execution stops abruptly.
On Error { GoTo [ line | 0 | -1 ] | Resume Next }
Example:
Public Sub OnErrorDemo()
On Error GoTo ErrorHandler ' Enable error-handling routine.
Dim x, y, z As Integer
x = 50
y = 0
z = x / y ' Divide by ZERO Error Raises
ErrorHandler: ' Error-handling routine.
Select Case Err.Number ' Evaluate error number.
Case 10 ' Divide by zero error
MsgBox ("You attempted to divide by zero!")
Case Else
MsgBox "UNKNOWN ERROR - Error# " & Err.Number & " : " & Err.Description
End Select
Resume Next
End Sub