private void GetAndAddOrderrowsToOrderhead(OrderHead orderhead)
        {
            var sessionOrderrow = CartManger.Items;
            foreach (var cartItem in sessionOrderrow)
            {
                var orderrow = new OrderRow();
                orderrow.OrderHeadID = orderhead.OrderHeadID;
                orderrow.ProductID = cartItem.ProductID;
                orderrow.Quantity = cartItem.Quantity;
                orderrow.ProductName = cartItem.ProductName;
                orderrow.ProductNumber = (db.Products
                                            .Where(p => p.ProductID == cartItem.ProductID)
                                            .Select(p => p.ProductNumber)).FirstOrDefault();
                orderrow.ProductPrice = cartItem.ProductPrice;

                db.OrderRows.InsertOnSubmit(orderrow);
                db.SubmitChanges();
            }
        }
 partial void DeleteOrderRow(OrderRow instance);
 partial void UpdateOrderRow(OrderRow instance);
 partial void InsertOrderRow(OrderRow instance);
		private void detach_OrderRows(OrderRow entity)
		{
			this.SendPropertyChanging();
			entity.OrderHead = null;
		}
		private void attach_OrderRows(OrderRow entity)
		{
			this.SendPropertyChanging();
			entity.OrderHead = this;
		}