VS 2008 [RESOLVED] Error handling question... Where did it come from?

[tassa]

Hello,

I'm wondering if there is any way to know where did the error come from. I have this:

Try
                Select Case MathOperation
                    Case Divide
                        'Divide a/b
                    Case Multiply
                        'Multiply a*b
                    Case Tangent
                        'Calculate tangent
                End Select
            Catch ex As Exception
                Return "Error"
            End Try 

When I say "where did the error come from, is which case threw the error.I know I could check the values and throw an exception, but I want to know which case produced the exception.

I hope it's clear .

Thanks in advance!

PS: That's just an example.

[kebo]

You can get the line number through the exception's StackTrace property, but to get the actual case, you would probably need to do a second case select in the exception block

Try
                      Select Case MathOperation
                          Case Divide
                              'Divide a/b
                          Case Multiply
                              'Multiply a*b
                          Case Tangent
                              'Calculate tangent
                      End Select
                  Catch ex As Exception

                      Select Case MathOperation
                          Case Divide
                            'Divide exception
                          Case Multiply
                              'Multiply exception
                          Case Tangent
                              'Calculate exception
                      End Select


                      Return "Error"
                  End Try 

[tassa]

Oh great!!! THANKS!!!

[danasegarane]

You have to get the details from the Stack Trace Only.

I won't go with the method suggested by kebo, though it is good. This will increase the complexity of the Program. As you have the MathOperation varriable in the Try block you can always check the text of this varriable and get the case which cause the Exception as

Dim MathOperation As String = "Divide"
        Try
            Select Case MathOperation
                Case "Divide"
                    Dim x As Integer = Convert.ToInt16("D")
                Case "Multiply"
                    'Multiply a*b

                    'Calculate tangent
            End Select
        Catch ex As Exception
            MessageBox.Show("Error came from " & MathOperation)
        End Try

[kebo]

yea... that would certainly simplify things

[jmcilhinney]

Depending on what you actually intend to do in the Catch block, a separate exception handler for each Case might be the most appropriate option.

[tassa]

Ok, thanks a lot guys .