windowedMyApp/WindowedMyApp/ActiveWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace WindowedMyApp
{
    /// <summary>
    /// Логика взаимодействия для ActiveWindow.xaml
    /// </summary>
    public partial class ActiveWindow : Window
    {
        public ActiveWindow()
        {
            InitializeComponent();

            MainFrame.frame = ActiveFrame;           
        }

        private void toTour_Click(object sender, RoutedEventArgs e)
        {
            MainFrame.frame.Navigate(new StartPage());
        }

        private void toGif_Click(object sender, RoutedEventArgs e)
        {
            MainFrame.frame.Navigate(new GifPage());
        }

        private void toDiagram_Click(object sender, RoutedEventArgs e)
        {
            MainFrame.frame.Navigate(new DiagramPage());
        }

        private void toUsersInfo_Click(object sender, RoutedEventArgs e)
        {
            MainFrame.frame.Navigate(new UsersInfo());
        }
    }
}