C# 图片框和计时器

Question

我正在尝试使用图片框和计时器创建汽车游戏

这是我的代码

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    PictureBox car = new PictureBox();
    Timer t = new Timer();

    private void Form1_KeyDown(object sender, KeyEventArgs e)
    {
        //Right arrow key
        if (e.KeyCode.Equals(Keys.Right) && carPlayer.Location.X < 300)
        {
            int x = carPlayer.Location.X + 5;
            int y = carPlayer.Location.Y;
            int width = carPlayer.Size.Width;
            int height = carPlayer.Size.Height;
            carPlayer.SetBounds(x, y, width, height);
        }

        //Left arrow key
        if (e.KeyCode.Equals(Keys.Left) && carPlayer.Location.X > 35)
        {
            int x = carPlayer.Location.X - 5;
            int y = carPlayer.Location.Y;
            int width = carPlayer.Size.Width;
            int height = carPlayer.Size.Height;
            carPlayer.SetBounds(x, y, width, height);
        }

        if (e.KeyCode.Equals(Keys.Space))
        {
            spawnCar();
        }
    }


    void spawnCar()
    {
        string[] cars = { "data/car_red.png", "data/car_blue.png", "data/car_green.png", "data/car_grey.png" };
        Random rand = new Random();
        car.SizeMode = PictureBoxSizeMode.StretchImage;
        car.Image = Image.FromFile(cars[rand.Next(0, 4)]);
        car.Visible = true;

        if (rand.Next(0,2) == 0)
        {
            car.SetBounds(100, 10, 50, 85);
        }
        else
        {
            car.SetBounds(250, 10, 50, 85);
        }

        this.Controls.Add(car);
        car.BringToFront();

        t.Interval = 1;
        t.Tick += new EventHandler(t_Tick);
        t.Start();
    }

    private void t_Tick(object sender, EventArgs e)
    {
        if (car.Bounds.IntersectsWith(carPlayer.Bounds))
        {
            t.Stop();
            car.Image = Image.FromFile("data/car_wreck.png");
            carPlayer.Image = Image.FromFile("data/player_wreck.png");
        }
        if (car.Bounds.Y > 340)
        {
            t.Stop();
            this.Controls.Remove(car);
        }
        else
        {
            car.Top++;
        }
    }
}

http://i.stack.imgur.com/NhCgY.png

现在，当我在汽车出现在顶部并缓慢向下移动并在到达底部时消失时按空格，但是当我多次按空格时，汽车的速度会越来越快。 任何人都请帮我让汽车在每次创建时都以相同的速度移动。

谢谢

Answer 1

问题是您在每次生成汽车时都注册了一个新的Tick 事件处理程序，您只想这样做一次。但是，没有一种简单的方法可以检查是否已分配处理程序，因此我建议使用全局标志...

//at class level
bool eventSet = false;

//in spawn method
t.Interval = 1;
if(!eventSet)//check if no handler assigned yet
{
    t.Tick += new EventHandler(t_Tick);
    eventSet = true;
}
t.Start();

或者，您可以尝试在分配之前删除处理程序...

//in spawn method
t.Interval = 1;
t.Tick -= new EventHandler(t_Tick);//remove previous one if it exists
t.Tick += new EventHandler(t_Tick);
t.Start();