为什么积分达到17会报错

Question

namespace Snake
{
    public partial class Form1 : Form
    {
        Label[] Snake_Body = new Label[500];//巨蟒身体数组，由label实例(标签)构成
        Label food = new Label();           //食物
        string Keyname = "stop";            //按键状态
        int x, y,b=0;
        int Snake_Long = 0, Snake_Tail_x, Snake_Tail_y;
        Random R = new Random();//随机数
        
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Makefood();//创建食物
            for (int i = 0; i < 5; i++)
            {
                Label Snaker = new Label();//创造五个初始巨蟒身体实例
                Snaker.Height = 10;
                Snaker.Width = 10;
                Snaker.Top = 300;
                Snaker.Left = 150 - i * 10;
                Snaker.BackColor = Color.DeepPink;
                Snaker.Text = " ";
                Snaker.Tag = i;
                Snake_Body[i] = Snaker;
                this.Controls.Add(Snaker);
            }
            timer1.Tick += new EventHandler(timer1_Tick);
            timer1.Start();
        }
        private void START_Click(object sender, EventArgs e)
        {
            Keyname = "start";//开始游戏
        }
        private void STOP_Click(object sender, EventArgs e)
        {
            Keyname = "stop";//暂停游戏
        }
        private void button1_Click(object sender, EventArgs e)//上
        {
            Keyname = "up";//上
        }
        private void LEFT_Click(object sender, EventArgs e)
        {
            Keyname = "left";//左
        }
        private void RIGHT_Click(object sender, EventArgs e)
        {
            Keyname = "right";//右
        }
        private void DOWN_Click(object sender, EventArgs e)
        {
            Keyname = "down";//下
        }
        private void timer1_Tick(object sender, EventArgs e)
                {
            b++;//目前不知道为啥定时器每到时间会进入两次，此处b使每到时间执执行一次
            if (b == 10)
                b = 0;
            if (b % 2 == 1)
            {
            ;
            }
            else
            {
                x = Snake_Body[0].Left;
                y = Snake_Body[0].Top;
                if (Keyname == "start")
                {
                    Snake_Body[0].Left += 10;
                }
                if (Keyname == "up")
                {
                    Snake_Body[0].Top -= 10;
                }
                if (Keyname == "down")
                {
                    Snake_Body[0].Top += 10;
                }
                if (Keyname == "left")
                {
                    Snake_Body[0].Left -= 10;
                }
                if (Keyname == "right")
                {
                    Snake_Body[0].Left += 10;
                }
                if (Snake_Body[0].Left >= 450)
                {
                    Snake_Body[0].Left = 0;
                }
                if (Snake_Body[0].Left < 0)
                {
                    Snake_Body[0].Left = 450;
                }
                if (Snake_Body[0].Top >= 480)
                {
                    Snake_Body[0].Top = 0;
                }
                if (Snake_Body[0].Top < 0)
                {
                    Snake_Body[0].Top = 480;
                }
                if (Keyname != "stop")
                {
                    Snake_Move();
                }
                if (Snake_Body[0].Left == food.Left && Snake_Body[0].Top == food.Top)//巨蟒吃到食物
                {
                    food.Top = R.Next(0, 47) * 10;
                    food.Left = R.Next(0, 44) * 10;
                    Label Snaker = new Label();
                    Snaker.Height = 10;
                    Snaker.Width = 10;
                    Snaker.Top = Snake_Tail_y;
                    Snaker.Left = Snake_Tail_x;
                    Snaker.BackColor = Color.DeepPink;
                    Snaker.Text = " ";
                    Snaker.Tag = Snake_Long + 1;
                    Snake_Body[Snake_Long + 1] = Snaker;
                    this.Controls.Add(Snaker);
                }
            }
    }
        public void Snake_Move()//巨蟒移动
        {
            int i;
            Snake_Long = 0;
            for (i = 1; Snake_Body[i]!= null; i++)
            {
                Snake_Long++;
            }
            textBox2.Text = Convert.ToString(Snake_Long-4);//分数显示
            timer1.Interval = (int)(200 - Snake_Long * 10)+1;//随巨蟒长度增加，移动速度加快
            Snake_Tail_x = Snake_Body[Snake_Long].Left;
            Snake_Tail_y = Snake_Body[Snake_Long].Top;
            for (i = Snake_Long; i > 1; i--)
            {
                Snake_Body[i].Left = Snake_Body[i - 1].Left;
                Snake_Body[i].Top = Snake_Body[i - 1].Top;
            }
            Snake_Body[1].Left = x;
            Snake_Body[1].Top = y;
        }
            public void Makefood()//创造食物实例
        {
            food.Width = 10;
            food.Height = 10;
            food.Top = R.Next(0,47) * 10;//食物y位置0-470
            food.Left = R.Next(0,44) * 10;//食物x位置0-470
            food.Text = " ";
            food.BackColor = Color.DarkSlateBlue;
            this.Controls.Add(food);
        }
    }
}

Answer 1

1.timer1_Tick会进入两次是因为你在设计器里双击生成了timer1_Tick事件，那么事件+=的代码是在designer.cs里的
你在load里又手动+=了一次，事件函数绑定了2次
2.timer1.Interval的修改可以在每次吃到东西之后，而不是每次移动一格都去修改它，同理，分数之类的也不需要每个周期都计算
3.你可以使用list来存label，而不要用数组，数组是定长的。就算要维护一个Snake_Long，你把它定义成全局变量，在吃到东西的时候++就行了，每次循环去求它实在没必要
4.报错是报什么错，先分析报错可能原因，然后断点跟，看到底哪一步出错，再对应的改