Android Question How to Raise and Propagate Exceptions with Known Messages

Sub Activity_Create(FirstTime As Boolean)
Try
    RecursiveCopy("A")
Catch
    Log(LastException.Message)
    If LastException.Message.Contains("Copying cancelled") Then
        Msgbox("Copy operation cancelled", "Confirmation")
    Else
        Msgbox(LastException.Message, "Error Occurred")
    End If
End Try
End Sub

Sub RecursiveCopy(sTarget As String)
Try
    Dim ex As ExceptionEx
   
    If sTarget.Length < 4 Then
        RecursiveCopy("B/" & sTarget)
    End If
    Log("Now processing: " & sTarget)
    If sTarget = "B/B/A" Then            ' We want to just skip this one, but carry on processing
        ex.Initialize("File Skipped")
        ex.Throw
    Else If sTarget = "B/A" Then        ' We want to cancel at this point, but return a meaningful exception
        ex.Initialize("Copying cancelled")
        ex.Throw
    End If

Catch
    If ex.IsInitialized Then
        If ex.Message = "File Skipped" Then
            Log("File copy skipped as requested")
        Else If ex.Message = "Copying cancelled" Then
            ex.Throw                    ' Re-raise for handling at next level
        End If
    Else If LastException.Message.Contains("Copying cancelled") Then
        ex.Initialize("Copying cancelled")
        ex.Throw                    ' Re-raise for handling at next level
    Else
        Msgbox(LastException.Message, "Error Occurred")
    End If
End Try
End Sub