public OrderDetailViewModel(int orderId)
 {
     SelectedOrderDetail = new OrderDetailAux()
     {
         OrderId = orderId
     };
     AddOrderDetailCommand    = new MyICommand(OnAddCategory, CanAddCategory);
     UpdateOrderDetailCommand = new MyICommand(OnUpdateOrderDetail, CanUpdateOrderDetail);
     OrderId = orderId;
     LoadOrderDetail();
     UpdateTotal();
     //UpdateTotal();
 }
        public void LoadOrderDetail()
        {
            ObservableCollection <OrderDetailAux> orderDetails = new ObservableCollection <OrderDetailAux>();

            using (MFSContext context = new MFSContext())
            {
                var data = from od in context.OrderDetails
                           join p in context.Products on od.Product.ProductId equals p.ProductId
                           join o in context.Orders on od.Order.OrderId equals o.OrderId
                           where od.Order.OrderId == SelectedOrderDetail.OrderId
                           select new
                {
                    OrderDetailId = od.OrderDetailId,
                    Quantity      = od.Quantity,
                    Cost          = od.Cost,
                    ProductId     = p.ProductId,
                    ProductName   = p.Name,
                    OrderId       = o.OrderId
                };


                foreach (var or in data)
                {
                    OrderDetailAux orderDetail = new OrderDetailAux()
                    {
                        OrderDetailId = or.OrderDetailId,
                        ProductId     = or.ProductId,
                        ProductName   = or.ProductName,
                        OrderId       = or.OrderId,
                        Quantity      = or.Quantity,
                        Cost          = or.Cost
                    };

                    orderDetails.Add(orderDetail);
                }
            }
            OrderDetails = orderDetails;
        }