public Order(SP_Get_ItemListResult itemResult) { DBDataContext dbContext = new DBDataContext(); orderItemID = itemResult.orderItemID; itemName = itemResult.ItemName; quantity = itemResult.quantity; // other properties ... var additionals = dbContext.SP_Get_AdditionalsList(orderItemID); Additionals = new ObservableCollection <string>(); foreach (var item in additionals) { Additionals.Add(item.Additionals); } }