Question

In C#, WinForms, VS2008, .NET 3.5…

For this code:

static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {

        try
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new FormThatDividesByZero());
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }

    }
}

public partial class FormThatDividesByZero : Form
{
    public FormThatDividesByZero()
    {
        InitializeComponent();
    }

    private void DivideByZeroButton_Click(object sender, EventArgs e)
    {
        // Create a divide by zero exception.
        int a = 0;
        int b = 0;
        int c = a / b;
    }
}

Full source: http://forgefx.com/posts/ExceptionReporting.zip

When I run this small test project, via F5, from the development environment, the exception after clicking the DivideByZero button is caught and the message box triggers. When I run the project by double-clicking the .exe in the /bin/Debug folder, the exception is not caught and there is no message box – why is this the case?

When the .exe is launched from outside of the IDE, or with “Debug > Start Without Debugging” from within visual studio, I get an unhandled exception. My understanding was that the code above would catch all exceptions.

Answer 1

This isn’t good way to catch global exception. You can use AppDomain or Application object to catch it. This object catch all unhandled exception and call event.

static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {

            AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException);
            Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(Application_ThreadException);
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new FormThatDividesByZero());            

    }

    static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)
    {
        Exception ex = (Exception)e.ExceptionObject;
        MessageDialog.Show(ex.Message);
        Application.Exit();
    }

    void Application_ThreadException(object sender, System.Threading.ThreadExceptionEventArgs e)
    {
        MessageDialog.Show(e.Exception.Message);
    }
}



public partial class FormThatDividesByZero : Form
{
    public FormThatDividesByZero()
    {
        InitializeComponent();
    }

    private void DivideByZeroButton_Click(object sender, EventArgs e)
    {
        // Create a divide by zero exception.
        int a = 0;
        int b = 0;
        int c = a / b;
    }
}