private void EditOrderButton_OnClick(object sender, RoutedEventArgs e)
        {
            Button button = sender as Button;
            Order  copy   = new Order(button.DataContext as Order);
            var    dialog = new AddModifyOrderDialog(copy, _viewModel.customizedProductRepository.CustomizedProductRepository.ToList(),
                                                     _viewModel.Employees.ToList(), _viewModel.Customers.ToList(),
                                                     _viewModel.Toppings.ToList(), _viewModel.Products.ToList());

            dialog.Owner = this;
            dialog.ShowDialog();
            if (dialog.DialogResult == true)
            {
                copy.OrderStatus      = OrderStatus.Cooking;
                copy.CookingDeadline  = DateTime.Parse("15/11/2017 9:00");
                copy.DeliveryDeadline = DateTime.Parse("15/11/2017 9:00");
                copy.OrderCreated     = DateTime.Parse("15/11/2017 9:00");
                copy.TotalPrice       = 0;

                copy.Deliveryman     = dialog.ModifyOrders.SelectedDeliveryman;
                copy.Customer        = dialog.ModifyOrders.SelectedCustomer;
                copy.OrderedProducts = dialog.ModifyOrders.Order.OrderedProducts;
                for (int i = 0; i < _viewModel.Orders.Count; i++)
                {
                    if (_viewModel.Orders[i].OrderId == copy.OrderId)
                    {
                        _viewModel.OrdersRepository.ChangeOrder(_viewModel.Orders[i], copy);
                        _viewModel.Orders[i] = copy;
                        DataContext          = null;
                        DataContext          = _viewModel;
                    }
                }
            }
        }
        private void AddOrderButton_OnClick(object sender, RoutedEventArgs e)
        {
            var dialog = new AddModifyOrderDialog(null, _viewModel.customizedProductRepository.CustomizedProductRepository.ToList(),
                                                  _viewModel.Employees.ToList(), _viewModel.Customers.ToList(),
                                                  _viewModel.Toppings.ToList(), _viewModel.Products.ToList());

            Order copy = new Order();

            dialog.Owner = this;
            dialog.ShowDialog();
            if (dialog.DialogResult == true)
            {
                copy.Deliveryman = dialog.ModifyOrders.SelectedDeliveryman;
                copy.Customer    = dialog.ModifyOrders.SelectedCustomer;

                // wypełnienie pól not null niebędących w formularzu
                copy.OrderedProducts  = dialog.ModifyOrders.Order.OrderedProducts;
                copy.OrderStatus      = OrderStatus.Cooking;
                copy.CookingDeadline  = DateTime.Parse("15/11/2017 9:00");
                copy.DeliveryDeadline = DateTime.Parse("15/11/2017 9:00");
                copy.OrderCreated     = DateTime.Parse("15/11/2017 9:00");
                copy.TotalPrice       = 0;

                _viewModel.OrdersRepository.AddNewOrder(copy);
                _viewModel.Orders.Add(copy);
                DataContext = null;
                DataContext = _viewModel;
            }
        }