/// <summary>
        /// Executing handler for when the Quit Game menu entry is selected.
        /// </summary>
        void QuitGameMenuEntrySelected(object sender, PlayerIndexEventArgs e)
        {
            const string message = "Are you sure you want to quit this game?";

            MessageBoxScreen confirmQuitMessageBox = new MessageBoxScreen(message);

            confirmQuitMessageBox.Accepted += ConfirmQuitMessageBoxAccepted;

            ScreenManager.AddScreen(confirmQuitMessageBox, ControllingPlayer);
        }
        /// <summary>
        /// When the user cancels the main menu, ask if they want to exit the sample.
        /// </summary>
        protected override void OnCancel(PlayerIndex playerIndex)
        {
            const string message = "Are you sure you want to exit this sample?";

            MessageBoxScreen confirmExitMessageBox = new MessageBoxScreen(message);

            confirmExitMessageBox.Accepted += ConfirmExitMessageBoxAccepted;

            ScreenManager.AddScreen(confirmExitMessageBox, playerIndex);
        }