public static List<Page> pages = new List<Page>();
        private static TerminalWindow _windowMain;
        public TerminalWindow()
        {
            Terminal.ReadFromIni();
            InitializeComponent();
            _windowMain = this;

            Terminal.Logger.Debug("Создание страниц");
            var v_order_headers = new V_OrderHeaders();
            var v_order_details = new V_OrderDetails();
            var v_weight_picking = new V_WeightPicking();
            var v_weights_delete = new V_WeightsDelete();

            //добавляем
            pages.Add(v_order_headers);
            pages.Add(v_order_details);
            pages.Add(v_weight_picking);
            pages.Add(v_weights_delete);
            Terminal.Logger.Debug("Страницы созданы");

            Terminal.Logger.Debug("Переключение на страницу V_OrderHeaders");
            SwitchPage(typeof(V_OrderHeaders));
            Routine();
        }
        public static TerminalWindow WindowMain
        {
            get { return _windowMain; }
        }
        public static Page GetPage(Type _type_ofpage)
        {
            return pages.Find(_p => _p.GetType().FullName.Equals(_type_ofpage.FullName));
        }
        private static Stack<Type> BackStack = new Stack<Type>(2);
        private static bool isFirst = true;
        public void SwitchPage(Type _type_ofpage)
        {
            Terminal.Logger.Debug("Переключение на страницу " + _type_ofpage.Name);
            if (isFirst)
            {
                Switch(_type_ofpage);
                isFirst = false;
                return;
            }
            BackStack.Push(SwitcherFrame.Content.GetType());
            BackStack.TrimExcess();
            Switch(_type_ofpage);
        }
        public void SwitchPageBack()
        {
            //var t = BackStack.Pop();
            if (BackStack.Count > 0)
                Switch(BackStack.Pop());
            //SwitchPage(BackStack.Pop());
        }
        private void Switch(Type _type_ofpage)
        { SwitcherFrame.Navigate(pages.Find(_p => _p.GetType().FullName.Equals(_type_ofpage.FullName))); } 

        public static Type LastPageType
        {
            get
            {
                if (BackStack.Count > 0)
                    return BackStack.Peek();
                return null;
            }
        }

    public partial class V_OrderHeaders
    {
        private readonly VM_OrderHeaders _vm = new VM_OrderHeaders();
        public V_OrderHeaders()
        {
            InitializeComponent();
            Initialized += Load;
            Unloaded += UnLoad;
            DataContext = _vm;
        }
        void Load(object sender, EventArgs e)
        {
            _vm.Load();
        }
        void UnLoad(object sender, RoutedEventArgs e)
        {
            _vm.UnLoad();
        }
    }