private void ButtonAddProduct_Click(object sender, RoutedEventArgs e) { try { var name = ComboBoxProducts.Text; var product = Products.GetProduct(name); product.Price = double.Parse(TextBoxPrice.Text); product.Quantity = double.Parse(TextBoxQuantity.Text); product.Cost = product.Price * product.Quantity; newDelivery.AddProduct(product); ResetFields(); LabelCostOfProducts.Content = newDelivery.CostOfProducts; } catch (Exception exception) { MessageBox.Show("Sprawdź poprawność wprowadzonych danych.\nSzczegóły: " + exception.Message, "Błąd!"); } }