<C#>多线程

using System.Threading;
delegate void dFunc(string text);
dFunc dFun1;
private Thread thread;
private void button1_Click(object sender, EventArgs e)
{
        thread = new Thread(new ThreadStart(fun));
        label1.Text = "0";
        thread.Start();
        button1.Enabled=false;
        button2.Enabled=true;
}
private void button2_Click(object sender, EventArgs e)
{
        if(thread.Abort())
        {
               button1.Enabled=true;
               button2.Enabled=false;    
         }
}
public void fun()
{
       while(true)
        {
               int x = Convert.ToInt32(label1.Text);
               x++;
               string s = Convet.ToString();
               label1.Invoke(dFun1,new object[]{s});
               Thread.Sleep(1000);
        }
}
private void Form1_FormClosing(object sender,FormClosingEventArgs e)
{
     if(thread.IsAlive)
          thread.Abort();
}