[2005] Stopping current execution

Sorry if this is a basic question but can I terminate the actions of parent subs from within a lower sub?

For example;

VB Code:

Private Sub MainSub
  For i = 1 To 500
    TopSub()
  Next
End Sub
 
Private Sub TopSub()
    For i = 1 to 1000 
    'Call the lower sub
    LowerSub()
  Next
End Sub
 
Private Sub LowerSub() 
  Try
    'Do stuff
  Catch
    'I want to be able to terminate any further execution of "Main"
    'from here if things go badly wrong (but leave the form up)
  End Try
End Sub

So if the user clicks a button which calls the MainSub and something nasty happens, I dont want the execution to continue through all remaining loops, but I also dont want to close the application.

Since some subs are functions, it makes it hard to pass an "OK" var up from each and every sub to its parent. I'm hoping there's a nifty command like Application.StopExecution(MainSub) or similar.

I have this issue because I'm cycling through file accesses over the internet and if I get an authentication error or a timeout, I want to offer the user the opportunity to abort any further processing and let them fix the problem.

Catch the exception at a higher level. You can either not catch the exception in LowerSub or else assign it to the InnerException of a new exception and throw that. That exception will then propagate back up the call stack and you can catch it wherever you need notification to occur.

ok, I think I get it, so is this the principal?

VB Code:

Private Sub MainSub
  Try
  For i = 1 To 500
    TopSub()
  Next
  Catch ex As Exception
    If TypeOf ex.InnerException Is LowerSubException Then
      'Report nasty things
    End If
  End Try
End Sub
 
Private Sub TopSub()
    For i = 1 to 1000 
    'Call the lower sub
    LowerSub()
  Next
End Sub
 
Private Sub LowerSub() 
  Try
    'Do stuff
  Catch ex As LowerSubException
    'Do nothing here?
  End Try
End Sub

No. Read my post again. I gave two options and that code isn't using either of them.

Also, you would never use a generic Catch block and then test the type of the exception like that. You write a Catch block specific to the type of exception you want to catch. If you don't care the type of exception then you just catch an Exception object. If you only want to catch a particular type of excepton then you specify that in the Catch statement.