Initialize ViewModel in GamePage of a C#/XAML MonoGame app

GamePageWithXaml.cs

public GamePage(LaunchActivatedEventArgs args)  
{
    InitializeComponent();

    // Add the data context
    DataContext = ScoreViewModel.Instance;

    // Create the game.
    _game = XamlGame<Game1>.Create(args, Window.Current.CoreWindow, this);
}