Move your event handler definition outside the class constructor. For example:
namespace TripLog.Views
{
public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
BindingContext = new MainViewModel();
}
void New_Clicked(object sender, EventArgs e)
{
Navigation.PushAsync(new NewEntryPage());
}
async void Trips_ItemTapped(object sender, ItemTappedEventArgs e)
{
var trip = (TripLogEntry)e.Item;
await Navigation.PushAsync(new DetailPage(trip));
trips.SelectedItem = null;
}
}
}