async void OnItemSelected(object sender, SelectedItemChangedEventArgs args)
        {
            var item = args.SelectedItem as MyPercorsiViewModel;

            if (item == null)
            {
                // the item was deselected
                return;
            }



            // Navigate to the detail page
            var detailvm = new MyDettaglioPercorsoViewModel(item);
            var detail   = new DettaglioPercorso();

            detail.BindingContext = detailvm;
            //Disabilitare bottone recensione
            var b = (Button)detail.FindByName("Recensione");

            b.IsVisible = false;
            await Navigation.PushAsync(detail);

            // Manually deselect item
            lstView.SelectedItem = null;
        }
        async void OnItemSelected(object sender, SelectedItemChangedEventArgs args)
        {
            var item = args.SelectedItem as PercorsiViewModel;

            if (item == null)
            {
                // the item was deselected
                return;
            }

            // Navigate to the detail page
            var detailvm = new DettaglioPercorsoViewModel(item);
            var detail   = new DettaglioPercorso();

            detail.BindingContext = detailvm;
            await Navigation.PushAsync(detail);

            // Manually deselect item
            lstView.SelectedItem = null;
        }