//when a Delivery is committed, the dishes in the delivery is commiteed to db at one time public void CommitDelivery(Delivery pD) { DataContextDataContext dc = new DataContextDataContext(); dc.insert_delivery( (Guid?)pD.id, pD.userFrom, pD.customerName, pD.phone, pD.address, (DateTime?)pD.commitTime, (DateTime?)pD.deliveryTime ); foreach (DishQuota dq in pD.dishQuotaList) { dc.insert_delivery_dish((Guid?)dq.id, pD.id, dq.dishName, (int?)dq.quota, dq.note); } }