private void Page_Loaded(object sender, RoutedEventArgs e) { ServiceProduct serviceProduct = new ServiceProduct(); products = serviceProduct.All(); productsFiltered = new ObservableCollection <Product>(products); ListViewAvailableProducts.ItemsSource = productsFiltered; ProductsRequiredInRecipe = new ObservableCollection <Product>(); ListViewProductsRequired.ItemsSource = ProductsRequiredInRecipe; }