Program.cs

using System;

namespace HelloWorld
{
    class Program
    {
        [STAThread]
        static void Main(string[] args)
        {
            App app = new App();

            Bootstrapper bootstrapper = new Bootstrapper();
            bootstrapper.Run();

            app.Run();
        }
    }
}

using System.Windows;

namespace HelloWorld
{
    /// <summary>
    /// Interaction logic for App.xaml
    /// </summary>
    public partial class App : Application
    {
        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);
            this.InitializeComponent();
        }
    }
}