winform中出现“程序停止响应”，如何再起一个线程？

Question

        private void button_Click(object sender, EventArgs e)
        {
            Task t1 = Task.Factory.StartNew(Copy);
        }        private void Copy()
        {
            File.Copy(sourceFileName,destFileName); 
        }

Answer 1

  private void button3_Click(object sender, EventArgs e)
        {
            Thread th = new Thread(Copy);
            th.IsBackground = true;
            th.Start();
        }        private void Copy()
        {
            File.Copy(sourceFileName, destFileName);
        }

Answer 2

        private void button_Click(object sender, EventArgs e)
        {
            CancellationTokenSource ct = new CancellationTokenSource();
            Task t1 = Task.Factory.StartNew(Copy);
            //停止
            ct.Cancel();
        }        private void Copy()
        {
            File.Copy(sourceFileName, destFileName); 
            //弹出对话框
            MessageBox.Show("已拷贝完成", "完成", MessageBoxButtons.OKCancel);
        }

Answer 3

唔，好像弄错了..
        private void button_Click(object sender, EventArgs e)
        {
            CancellationToken ct = new CancellationToken();
            Task t1 = Task.Factory.StartNew(Copy,ct);
            //停止
            ct.ThrowIfCancellationRequested();
        }

Answer 4

Action.BeginInvoke
Action.EndInvoke