Application.Current.Shutdown(-1) not closing WPF app

Question

I am checking if the windows authenticated user is a valid user for my wpf application or not.

If not, I need to shut down the application; but even after executing Application.Current.Shutdown(-1) the application keeps on executing happily.

The below link says that I need to remove my StartUpURI; but I dont have that tag in my app.xaml. -> Shutting down a WPF application from App.xaml.cs

EDIT :- I have this code in APP.XAML.CS ->

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

            this.exceptionPolicy = ConfigurationManager.AppSettings.Get("ExceptionPolicy");
            this.displayErrorDetails = true;
            this.container = new UnityContainer();

            // Register services and types in Unity
            RegisterServices();

            // Check user
            if (!IsValidUser())
            {
                //Application.Current.Shutdown(); 
                App.Current.Shutdown();
            }

        }

Answer 1

Use Environment.Exit() instead. That will try to shut down gracefully, but if it can't gracefully, will shut down rudely -- forcefully terminating threads.