//Переход по меню
        private void ListViewMenu_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            int index = ListViewMenu.SelectedIndex;

            switch (index)
            {
            case 0:
                FrameCh.Navigate(page1);
                ChangeIcon.Kind   = MaterialDesignThemes.Wpf.PackIconKind.Airport;
                ChangeHeader.Text = "РАСПИСАНИЕ";
                break;

            case 1:
                FrameCh.Navigate(page2);
                ChangeIcon.Kind   = MaterialDesignThemes.Wpf.PackIconKind.Aeroplane;
                ChangeHeader.Text = "САМОЛЕТЫ";
                break;

            case 2:
                FrameCh.Navigate(page3);
                ChangeIcon.Kind   = MaterialDesignThemes.Wpf.PackIconKind.UserSupervisorCircle;
                ChangeHeader.Text = "АВИАКОМПАНИИ";
                break;

            case 3:
                FrameCh.Navigate(page4);
                ChangeIcon.Kind   = MaterialDesignThemes.Wpf.PackIconKind.FileDocument;
                ChangeHeader.Text = "ОТЧЕТ";
                break;
            }
        }
        public Window1()
        {
            InitializeComponent();
            FrameCh.Navigate(page1);
            ChangeIcon.Kind   = MaterialDesignThemes.Wpf.PackIconKind.Airport;
            ChangeHeader.Text = "РАСПИСАНИЕ";

            TextboxFI.Text = $"{CurrentUser.SecondName} {CurrentUser.FirstName}";
        }
 //Открыть справку
 private void ButtonClick_help(object sender, RoutedEventArgs e)
 {
     FrameCh.Navigate(helpPage5);
     ChangeIcon.Kind   = MaterialDesignThemes.Wpf.PackIconKind.HelpOutline;
     ChangeHeader.Text = "СПРАВКА";
 }