void quitGameMenuEntrySelected(object sender, PlayerIndexEventArgs e)
 {
     const string message = "Are you sure you want to quit?";
     MessageBoxScreen confirmQuitMessageBox = new MessageBoxScreen(message);
     confirmQuitMessageBox.Accepted += confirmQuitMessageBoxAccepted;
     ScreenManager.AddScreen(confirmQuitMessageBox, ControllingPlayer);
 }
        // When the user cancels the main menu, ask if they want to exit.
        protected override void OnCancel(PlayerIndex playerIndex)
        {
            const string message = "Are you sure you want to exit?";

            MessageBoxScreen confirmExitMessageBox = new MessageBoxScreen(message);

            confirmExitMessageBox.Accepted += confirmExitMessageBoxAccepted;

            ScreenManager.AddScreen(confirmExitMessageBox, playerIndex);
        }