先说一下我的问题：主要就是想实现（winform中）
1.在时钟里更新数组，
2.在一个线程中利用这个数组的值画出曲线。
下面是我写的程序，图就画了一次不知道怎么回事？请高手指教。。。。


using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Threading;

namespace WindowsApplication3
{
    public partial class Form1 : Form
    {
        static  int[] a = new int[10];
        static int[] b = new int[10];
        static int count = 0;
        Object obj = new Object();//
        public Form1()
        {
            InitializeComponent();
        }
        private void draw()
        {
            Graphics g = pictureBox1.CreateGraphics();
            Pen pen1 = new Pen(Color.Red, 2);
            g.Clear(Color.White);
            lock (a)
            {
                for (int i = 0; i < 9; i++)
               g.DrawLine(pen1, a[i], b[i], a[i + 1], b[i + 1]);
            }
        }
        private void timer1_Tick(object sender, EventArgs e)
        {
            lock (a)
            {
                    for (int i = 0; i < 10; i++)
                    {
                        a[i] = (50 + count * 10) * i;
                        if (i % 2 == 0) b[i] = 30;
                        else b[i] = 50;
                    }
                    if (count < 10) count++;
                    else count = 0;
            }
            
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            for (int i = 0; i < 10; i++)
            {
                a[i] = 50 * i;
                if (i % 2 == 0)b[i] = 30;
                else b[i] = 50;
            }
           
        }

        private void button1_Click(object sender, EventArgs e)
        {
            ThreadStart ts = new ThreadStart(draw);
            Thread thread = new Thread(ts);
            thread.Start();
            timer1.Enabled = true;
        }
    }
}

来人啊

按钮里执行了一个线程，线程执行完毕就被系统回收了。线程就没了。