C# WinForm-Timer控件的使用

public Form6()
    {
      InitializeComponent();

      while (true)
      {
        label1.Text = DateTime.Now.ToString("yyyy年MM月dd日hh时mm分ss秒");
        System.Threading.Thread.Sleep(1000);
      }
    }

public Form6()
    {
      InitializeComponent();

      
    }

    private void button1_Click(object sender, EventArgs e)
    {
      while (true)
      {
        label1.Text = DateTime.Now.ToString("yyyy年MM月dd日hh时mm分ss秒");
        System.Threading.Thread.Sleep(1000);
      }
    }

 //Timer控件 显示时间
    private void timer1_Tick(object sender, EventArgs e)
    {
      label1.Text = DateTime.Now.ToString("yyyy年MM月dd日hh时mm分ss秒");
    }

public Form6()
    {
      InitializeComponent();      
    }

    bool start = false;
    //开始或结束抽奖
    private void button1_Click(object sender, EventArgs e)
    {
      if(start==false)
      {
        timer1.Enabled = true;
        start = true;
        button1.Text = "停止";
      }
      else
      {
        timer1.Enabled = false;
        start = false;
        button1.Text = "开始";
      }
    }
    //Timer控件事件
    private void timer1_Tick(object sender, EventArgs e)
    {
      Random r = new Random();
      label1.Text = r.Next(1, 200).ToString();
    }