妙なことが起こった　Ｃ＃

有りません

public partial class FormPrincipal : Form
    {
        DispatcherTimer gameLoopTimer { get; set; }

        DispatcherTimer enemySpawnTimer { get; set; }

        Bitmap screenBuffer { get; set; }

        Graphics screenPainter { get; set; }

        BackGround backGround { get; set; }

        Player player { get; set; }

        List<GameObject> gameObjects { get; set; }

        public Random random { get; set; }

        public FormPrincipal()
        {
            InitializeComponent();


            this.random = new Random();
            this.ClientSize = Media.BackGround.Size;
            this.screenBuffer = new Bitmap(Media.BackGround.Width, Media.BackGround.Height);
            this.screenPainter = Graphics.FromImage(this.screenBuffer);
            this.gameObjects = new List<GameObject>();
            this.backGround = new BackGround(this.screenBuffer.Size, this.screenPainter);
            this.player = new Player(this.screenBuffer.Size, this.screenPainter);

            this.gameLoopTimer = new DispatcherTimer(DispatcherPriority.Render);
            this.gameLoopTimer.Interval = TimeSpan.FromMilliseconds(16.66666);
            this.gameLoopTimer.Tick += GameLoop;

            this.enemySpawnTimer = new DispatcherTimer(DispatcherPriority.Render);
            this.enemySpawnTimer.Interval = TimeSpan.FromMilliseconds(1000);
            this.enemySpawnTimer.Tick += SpawnEnemy;

            this.gameObjects.Add(backGround);
            this.gameObjects.Add(player);

            StartGame();
        }

        public void StartGame()
        {
            this.gameLoopTimer.Start();
            this.enemySpawnTimer.Start();
        }

        public void SpawnEnemy(object sender, EventArgs e)
        {
            Point enemyPosition = new Point(this.random.Next(74, this.screenBuffer.Width - 10) - 62);
            Enemy enemy = new Enemy(this.screenBuffer.Size, this.screenPainter, enemyPosition);
            this.gameObjects.Add(enemy);
        }

        public void GameLoop(object sender, EventArgs e)
        {
            this.gameObjects.RemoveAll(x => !x.Active);

            this.ProcessControls();

            foreach (GameObject go in this.gameObjects)
            {

                go.UpDateObject();

                if (go.IsOutOfBounds())
                {
                    go.Destroy();
                }


            }
            this.Invalidate();
        }

        private void FormPrincipal_Paint(object sender, PaintEventArgs e)
        {
            e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
            e.Graphics.DrawImage(this.screenBuffer, 0, 0);
        }

        private void ProcessControls()
        {
            if (Keyboard.IsKeyDown(Key.Left)) player.MoveLeft();
            if (Keyboard.IsKeyDown(Key.Right)) player.MoveRight();
            if (Keyboard.IsKeyDown(Key.Up)) player.MoveUp();
            if (Keyboard.IsKeyDown(Key.Down)) player.MoveDown();
        }

        private void FormPrincipal_Load(object sender, EventArgs e)
        {
            
        }
    }