WinForms - why aren't my exceptions caught?

Question

Hi, In my multithread server I am using following code (before running Form itself or course)

AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomainUnhandledException);
Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(ApplicationThreadException);

The called methods write exceptions to the list so I can fix it easily. But today I came and saw that VS has thrown NullReference exception and I have no clue why it was not catched?

I can reproduce it by calling: stream=null; stream.Flush()

The program do jump to exception catching scope but it stays on the Flush line..strange. Any other exception is handled well..maybe its beacuse this method is not implemented yet?

Im sure I have seen "Object reference not set to an instance of object" in my "exceptions" list and the program continued. Why isn't this particular exception caught?

Answer 1

To answer your question, we need more information about the error that was thrown. Does it originate from your code? Let's see the stack trace.

Also, if you call Application.Run(...) before setting up the ThreadException, it won't catch any exceptions.

Answer 2

Hi there,

We use the following code and find it works well: -

namespace YourNamespace
{
    static class Program
    {

        [STAThread]
        static void Main()
        {
            AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;
            Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(Application_ThreadException);
            Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException);
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }

        static void Application_ThreadException(object sender, System.Threading.ThreadExceptionEventArgs e)
        {
            HandleException(e.Exception);
        }

        static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)
        {
            HandleException((Exception)e.ExceptionObject);
        }

        static void HandleException(Exception e)
        {
            //Handle exception
        }

    }
}

Thanks,

Phil http://exceptioneer.com