DataTemplate not appeared in Application_Startup

Question

I'm making a splash screen in App.cs. When I use SplashWorker.RunWorkerAsync(); DataTemplate not appeared.
but when annotating this code, DataTemplate was appeared....

It is properly registered ViewModel and ResourceDictionary.

App.xaml

<Application ..........   Startup="Application_Startup">

App.cs

private void Application_Startup(object sender, StartupEventArgs e)
{
    this.ShutdownMode = ShutdownMode.OnExplicitShutdown;

    SplashWindow sw = new SplashWindow();

    sw.Closed += (ss, ee) =>
    {
        if (ServiceLocator.Current.GetInstance<SplashViewModel>().ClosedByUser)
        {
            this.Shutdown();
        }
        ServiceLocator.Current.GetInstance<SplashViewModel>().Cleanup();
        sw = null;
    };

    if ((bool)sw.ShowDialog())
    {
        this.ShutdownMode = ShutdownMode.OnMainWindowClose;
        MainWindow = new MainWindow();
        MainWindow.Show();
    }
}

SplashViewModel.cs

 public SplashViewModel()
 {
     SplashWorker = new BackgroundWorker();
     SplashWorker.WorkerSupportsCancellation = true;
     SplashWorker.DoWork += SplashWorker_DoWork;
     SplashWorker.RunWorkerCompleted += SplashWorker_RunWorkerCompleted;
     Result = null;
     SplashWorker.RunWorkerAsync();
 }

private void Application_Startup(object sender, StartupEventArgs e)
{
    this.ShutdownMode = ShutdownMode.OnExplicitShutdown;

    SplashWindow sw = new SplashWindow();
    sw.Closed += (ss, ee) =>
    {
        if (ServiceLocator.Current.GetInstance<SplashViewModel>().ClosedByUser)
        {
            this.Shutdown();
        }
        ServiceLocator.Current.GetInstance<SplashViewModel>().Cleanup();
        sw = null;
    };

    sw.Loaded += (ss, ee) =>
    {
        ServiceLocator.Current.GetInstance<SplashViewModel>().RunWorker();
    };

    if ((bool)sw.ShowDialog())
    {
        this.ShutdownMode = ShutdownMode.OnMainWindowClose;
        MainWindow = new MainWindow();
        MainWindow.Show();
    }
}

Answer 1

As mentioned by @AnjumSKhan in the comments ,move your SplashWorker code in Startup event of the Application because DataTemplate would work while binding, which happens after InitializeComponent method.