Throwing exceptions multiple times

Question

I have the following code:

    static int GetLastAddedIDHelper(OleDbConnection connection)
    {
        try
        {
            // Init variables.
            OleDbCommand command = null;
            string cmdText = "SELECT @@IDENTITY";

            if (connection != null)
                command = new OleDbCommand(cmdText, connection);
            else
                throw new ArgumentNullException("connection", "The connection was passed as null. Therefore the globally used connection is used but was never set.");

            return (int)command.ExecuteScalar();
        }
        catch (Exception ex) { throw ex; }
    }

    public static int GetLastAddedID()
    {
        try
        {
            return GetLastAddedIDHelper(_Connection);
        }
        catch (Exception ex) { throw ex; }
    }

    private void Button_Click_Action()
    {
        try
        {
            int i = AccessDbServiceBase.GetLastAddedID();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ExceptionHandler.GetExceptionMessage(ex));
        }
    }

The above code will get the last inserted ID from an Access database for me. Now, to do this, Button_Click_Action will call GetLastAddedID and that will call GetLastAddedIDHelper. When a exception occurs in GetLastAddedIDHelper, I throw the exception up to the main method Button_Click_Action.

I'm wondering if I'm doing this the correct way like, is the throw in GetLastAddedID necessary, should I use throw instead of throw ex, ...?

Jason Boyd · Accepted Answer · 2015-04-11 21:50:55Z

2

The exception handling in GetLastAddedIDHelper and GetLastAddedID do not serve any useful purpose in this case. Your intent, it would seem, is to simply catch the exception and then do nothing with it except to rethrow it. If that is the case then why bother catching it all? Just let the exception propagate up the stack until an exception handler that can handle it gets it, in the Button_Click_Action method in this case.

In this example your exception handling is actually harmful because throw ex will mess up your stack trace. You want to use throw instead.

answered Apr 11, 2015 at 21:50

Jason Boyd

7,0495 gold badges33 silver badges53 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Krowi Over a year ago

So basically, if the methods GetLastAddedIDHelper and GetLastAddedID are only used in other methods that will have exception handling it's better to just leave the try...catch if throwing is the only thing I do?

Jason Boyd Over a year ago

Yep, that is the short of it. And if you do find yourself in a situation where you need to rethrow (you probably will not being doing this very often but there are some use cases) then use throw; to rethrow properly. You can search for 'C# rethrow' on Google for more details on why.

drs9222 · Accepted Answer · 2015-04-11 21:46:07Z

0

You probably want to do throw; because throw ex; will reset the stack trace.

answered Apr 11, 2015 at 21:46

drs9222

4,5183 gold badges35 silver badges42 bronze badges

Collectives™ on Stack Overflow

Throwing exceptions multiple times

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related