protected override async void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
        {
            string productId = NavigationContext.QueryString["ProductId"];

            var listings = await Windows.ApplicationModel.Store.CurrentApp.LoadListingInformationAsync();

            Product = listings.ProductListings.Single(l => l.Value.ProductId == productId).Value;
            this.DataContext = Product;

            base.OnNavigatedTo(e);
        }
        protected override async void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
        {
            string productId = NavigationContext.QueryString["ProductId"];

            var listings = await Windows.ApplicationModel.Store.CurrentApp.LoadListingInformationAsync();

            Product          = listings.ProductListings.Single(l => l.Value.ProductId == productId).Value;
            this.DataContext = Product;

            base.OnNavigatedTo(e);
        }