winform 使用委托 实现多线程访问控件

private delegate void FlushClient();//代理
private void ThreadFunction()
{
if (this.textBox1.InvokeRequired)
{
FlushClient fc = new FlushClient(ThreadFunction);
this.Invoke(fc);
}
else
{
string s = DateTime.Now.ToString("yyyy年MM月dd日 HH时mm分ss秒");
this.textBox1.Text = s;
// this.label1.Text = s;
}
}

private void CrossThreadFulush()
{
while (true)
{
Thread.Sleep(1000);
ThreadFunction();
}
}

private void button1_Click(object sender, EventArgs e)
{
Thread th = new Thread(CrossThreadFulush);
th.IsBackground = true;
th.Start();
}