吃豆子游戏 - 如何解决

Question

我正在制作非常简单的pacman游戏作为家庭作业。我在Visual Studio中使用c＃。问题是，当我点击运行时，只有winform显示没有任何内容。有人能告诉我，我做错了什么吗？

namespace pacman
{
    public partial class Form1 : Form
    {
        Timer timer;
        Pacman pacman;
        static readonly int TIMER_INTERVAL = 250;
        static readonly int WORLD_WIDTH = 15;
        static readonly int WORLD_HEIGHT = 10;
        Image foodImage;
        bool[][] foodWorld;

        public Form1()
        {
            InitializeComponent();

            foodImage = Properties.Resources.orange_detoure;
            DoubleBuffered = true;
            newGame();
        }

        public void newGame()
        {
            pacman = new Pacman();
            this.Width = Pacman.radius * 2 * (WORLD_WIDTH + 1);
            this.Height = Pacman.radius * 2 * (WORLD_HEIGHT + 1);

            foodWorld = new bool[WORLD_WIDTH][];

            timer = new Timer();
            timer.Interval = TIMER_INTERVAL;
            timer.Tick += new EventHandler(timer_Tick);
            timer.Start();
        }

        void timer_Tick(object sender, EventArgs e)
        {
            timer.Interval = TIMER_INTERVAL - 1;
            if (TIMER_INTERVAL == 0)
            {
                timer.Stop();
            }
            pacman.Move(WORLD_WIDTH, WORLD_HEIGHT);
            Invalidate();
        }

        private void Form1_KeyUp(object sender, KeyEventArgs e)
        {
            if (Keys.Up != 0) 
            {
                pacman.ChangeDirection("UP");
            }
            if (Keys.Down != 0)
            {
                pacman.ChangeDirection("DOWN");
            }
            if (Keys.Left != 0)
            {
                pacman.ChangeDirection("LEFT");
            }
            if (Keys.Right != 0)
            {
                pacman.ChangeDirection("RIGHT");
            }
            Invalidate();
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            g.Clear(Color.White);
            for (int i = 0; i < foodWorld.Length; i++)
            {
                for (int j = 0; j < foodWorld[i].Length; j++)
                {
                    if (foodWorld[i][j])
                    {
                        g.DrawImageUnscaled(foodImage, j * Pacman.radius * 2 + (Pacman.radius * 2 - foodImage.Height) / 2, i * Pacman.radius * 2 + (Pacman.radius * 2 - foodImage.Width) / 2);
                    }
                }
            }
            pacman.Draw(g);
        }
    }
}

以下是Pacman课程：

namespace pacman
{
    public class Pacman
    {
        public enum dir {UP, DOWN, RIGHT, LEFT}; 

        public float x { get; set; }
        public float y { get; set; }
        public string direction { get; set; }
        static public int radius = 20;
        public double speed { get; set; }
        public bool open { get; set; }
        public Brush brush = new SolidBrush(Color.Yellow);

        public Pacman() {
            this.x = 7;
            this.y = 5;
            this.speed = 20;
            this.direction = Convert.ToString(dir.RIGHT);
            this.open = false;
        }

        public void ChangeDirection(string direct)
        {
            // vasiot kod ovde
            for (int i = 0; i < 3; i++) { 

                if(direct == Convert.ToString(dir.RIGHT))
                {
                    direction = "RIGHT";
                }
                if (direct == Convert.ToString(dir.LEFT))
                {
                    direction = "LEFT";
                }
                if (direct == Convert.ToString(dir.UP))
                {
                    direction = "UP";
                }
                if (direct == Convert.ToString(dir.DOWN))
                {
                    direction = "DOWN";
                }
            }
        }

        public void Move(float width, float height)
        {
            if (direction == Convert.ToString(dir.RIGHT))
            {
                x = x + 1;
                if (x > width) {
                    x = 1;
                }
            }
            else if (direction == Convert.ToString(dir.LEFT))
            {
                x = x - 1;
                if (x < 0) {
                    x = 14;
                }
            }
            else if (direction == Convert.ToString(dir.UP))
            {
                y = y + 1;
                if (y > height) {
                    y = 1;
                }
            }
            else if (direction == Convert.ToString(dir.DOWN))
            {
                y = y - 1;
                if (y < 0) {
                    y = 14;
                }
            }
        }

        public void Draw(Graphics g)
        {
            if (!open) {
                g.FillEllipse(brush, 7, 5, 15, 15);
            }
        }   
    }
}

它看起来应该是http://prntscr.com/70e0jt。 如果有人能告诉我应该修复什么以便它最终有效，我将不胜感激。