public void SaveCartItems(IEnumerable <CartItem> cartItems)
        {
            var orders = _xMLReader.Read <OrdersXml>(DataFilesPaths.Orders);

            orders.Orders.Add(new Order {
                OrderItems = cartItems.ToList()
            });
            _xMLWriter.Write(DataFilesPaths.Orders, orders);
        }
        private void ReadAll()
        {
            var result = _xMLReader.Read <UsersXml>(DataFilesPaths.Users);

            _users = result.Users;
        }
        private void ReadAll()
        {
            var result = _xMLReader.Read <ProductsXml>(DataFilesPaths.Products);

            _products = result.Products;
        }