public SaleLineItem GetLineItem(Product product) { foreach (var sli in LineItems) if (sli.Product.Equals(product)) return sli; return null; }
public void AddLineItem(Product product, int quantity = 1) { SaleLineItem lineItem = GetLineItem(product); if (lineItem == null) { lineItem = new SaleLineItem { Product = product, }; LineItems.Add(lineItem); } lineItem.Quantity += quantity; }