public StockAccessoryForm(StockFormMode mode)
 {
     InitializeComponent();
     AccessoryFacade = new AccessoryFacade();
     InitForm(mode);
     Mode = mode;
 }
        private void InitForm(StockFormMode mode)
        {
            var categories = AccessoryFacade.GetCategories();

            CategoryComboBox.ItemsSource = categories;
            if (mode == StockFormMode.In)
            {
                TitleTextBlock.Text            = "Accept delivery of Accessory";
                CustomerNameTextBox.Visibility = Visibility.Collapsed;
                CustomerNameLabel.Visibility   = Visibility.Collapsed;
            }
            else if (mode == StockFormMode.Out)
            {
                TitleTextBlock.Text = "Hand over Accessory";
            }
            else
            {
                throw new ArgumentException("Unsupported form mode");
            }
        }