/// <summary>
        /// Responds to user input, changing the selected entry and accepting
        /// or cancelling the menu.
        /// </summary>
        public override void HandleInput(InputState input)
        {
            // Move to the previous menu entry?
            if (input.MenuUp)
            {
                selectedEntry--;

                if (selectedEntry < 0)
                    selectedEntry = menuEntries.Count - 1;
            }

            // Move to the next menu entry?
            if (input.MenuDown)
            {
                selectedEntry++;

                if (selectedEntry >= menuEntries.Count)
                    selectedEntry = 0;
            }

            // Accept or cancel the menu?
            if (input.MenuSelect)
                OnSelectEntry(selectedEntry);
        }
        /// <summary>
        /// Lets the game respond to player input. Unlike the Update method,
        /// this will only be called when the gameplay screen is active.
        /// </summary>
        public override void HandleInput(InputState input)
        {
            if (input == null)
                throw new ArgumentNullException("input");

            // Exit the game when back is pressed.
            if (input.IsExit)
                ScreenManager.Game.Exit();
        }
 /// <summary>
 /// Allows the screen to handle user input. Unlike Update, this method
 /// is only called when the screen is active, and not when some other
 /// screen has taken the focus.
 /// </summary>
 public virtual void HandleInput(InputState input)
 {
 }