/// <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);
            }
            else if (input.MenuCancel)
            {
                OnCancel();
            }
        }
        /// <summary>
        /// Input helper method provided by GameScreen.  Packages up the various input
        /// values for ease of use.  Here it checks for pausing and handles controlling
        /// the player's tank.
        /// </summary>
        /// <param name="input">The state of the gamepads</param>
        public override void HandleInput(InputState input)
        {
            if (input == null)
                throw new ArgumentNullException("input");

            //// Allows the game to exit
            //if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
            //    this.Exit();
            //if (Keyboard.GetState(PlayerIndex.One).IsKeyDown(Keys.Escape))
            //    this.Exit();

            if (input.PauseGame)
            {
                if (gameOver == true)
                {
                    foreach (GameScreen screen in ScreenManager.GetScreens())
                        screen.ExitScreen();

                    ScreenManager.AddScreen(new MainMenuScreen());
                }
                else
                {
                    ScreenManager.AddScreen(new PauseMenuScreen());
                }
            }
            else
            {
            }
        }
 /// <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)
 {
 }