public async static void CancelOrderAction(string data)
        {
            OrderBill canceledOder = JsonConvert.DeserializeObject <OrderBill>(data);

            //fetch data products in server
            await ServerDatabase.FetchProductData();

            //xóa orderbill
            DataUpdater.DeleteOrderBillByID(canceledOder.IDOrderBill);

            //update list order+số lượng product cho cửa hàng bị hủy order
            if (Infor.IDStore == canceledOder.IDStore)
            {
                (TabbarStoreManager.GetInstance().Children.ElementAt(1).BindingContext as ProductManagerViewModel).LoadData(true);
                (TabbarStoreManager.GetInstance().Children.ElementAt(2).BindingContext as OrderManagerViewModel).LoadData();
            }

            if (Infor.IDUser == canceledOder.IDUser)
            {
                (TabBarCustomer.GetInstance().Children.ElementAt(3).BindingContext as ListOrdersViewModel).LoadData();
            }

            //update số lượng product cho các user khác (gồm cả user là store bị hủy)
            var ShowStoreVM = ShowStoreView.GetInstance().BindingContext as ShowStoreViewModel;

            if (ShowStoreVM != null && ShowStoreVM.IDStore == canceledOder.IDStore)
            {
                ShowStoreVM.LoadData(true);
            }
        }
        public async static void InsertOrderBillAction(string data)
        {
            //fetch data products in server
            await ServerDatabase.FetchProductData();

            OrderBill newOrder = JsonConvert.DeserializeObject <OrderBill>(data);

            DataUpdater.InsertOrderBill(newOrder);
            if (Infor.IDStore == newOrder.IDStore)
            {
                (TabbarStoreManager.GetInstance().Children.ElementAt(2).BindingContext as OrderManagerViewModel).LoadData();
            }
        }