Shutting down a WPF application from App.xaml.cs

Question

I am currently writing a WPF application which does command-line argument handling in App.xaml.cs (which is necessary because the Startup event seems to be the recommended w

Answer 1

I did this a little differently to avoid having to set the StartupUri and ShutdownMode properties. First edit the App.xaml file and replace StartupUri with Startup:

Then add Application_Startup to the code along with OnExit:

public partial class App : Application
{
    private volatile static Mutex s_mutex;

    private void Application_Startup(object sender, StartupEventArgs e)
    {
        s_mutex = new Mutex(true, @"Global\MenuMutex", out bool grantedOwnership);

        if (!grantedOwnership)
        {
            MessageBox.Show($"Another instance is already running!", "Error", MessageBoxButton.OK, MessageBoxImage.Exclamation);
            Current.Shutdown();
        }
        else
            new MainWindow().Show();
    }

    protected override void OnExit(ExitEventArgs e)
    {
        s_mutex?.ReleaseMutex();
        s_mutex?.Dispose();
        s_mutex = null;
        base.OnExit(e);
    }