App.xaml.cs

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;

namespace WPF
{
    /// <summary>
    /// Логика взаимодействия для App.xaml
    /// </summary>
    public partial class App : Application
    {
        void Application_Startup(object sender, StartupEventArgs e)
        {
            StartupUri = new Uri("View/MainWindow.xaml", UriKind.Relative);
        }
    }
}