public partial class App : Application
{
    protected override void OnStartup(StartupEventArgs e)
    {
        AppDomain.CurrentDomain.UnhandledException 
            += new UnhandledExceptionEventHandler(UnhandledExceptionHandler);

        ServiceInjector.InjectServices();

        base.OnStartup(e);

        MainWindow window = new MainWindow();
        window.Show();
    }

    void UnhandledExceptionHandler(object sender, UnhandledExceptionEventArgs args)
    {
        var exceptionObj = args.ExceptionObject as Exception;
        if (exceptionObj == null)
            exceptionObj = new NotSupportedException(
                "Unhandled exception doesn't derive from System.Exception: " 
                + args.ExceptionObject.ToString());

        // TODO: Logging...

        var messageBox = GetService<IMessageBoxService>();
        messageBox.Show(
            exceptionObj.Message, 
            "Unhandled exception.",
            MessageBoxButton.OK,
            MessageBoxImage.Exclamation);

        Environment.Exit(1);
    }

    #region Resolve service dependencies members.
    
    public TServiceContract GetService<TServiceContract>()
        where TServiceContract : class
    {
        return ServiceContainer.Instance.GetService<TServiceContract>();
    }

    #endregion Resolve service dependencies members.
}