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

If you remove the StartupUri from app.xaml for an application with a MainWindow you need to make sure you make the following call in your OnStartup method otherwise the application will not terminate when your MainWindow closes.

this.ShutdownMode = System.Windows.ShutdownMode.OnMainWindowClose;

@Frank Schwieterman, something along these lines may help you with your console window issue.

Answer 2

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:

<Application x:Class="Menu.App"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:local="clr-namespace:Menu"
         Startup="Application_Startup">
    <Application.Resources>
    </Application.Resources>
</Application>

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);
    }

Answer 3

First remove the StartupUri property from App.xaml and then use the following:

    protected override void OnStartup(StartupEventArgs e)
    {
        base.OnStartup(e);

        bool doShutDown = ...;

        if (doShutDown)
        {
            Shutdown(1);
            return;
        }
        else
        {
            this.StartupUri = new Uri("Window1.xaml", UriKind.Relative);
        }
    }