C#

 

private void button4_Click(object sender, EventArgs e)
        {
            int marktime = 0;
            MyMethod my = method;
            IAsyncResult asyncResult = my.BeginInvoke(MethodCompleted, my);
            while (!asyncResult.IsCompleted && marktime < 4)
            {
                marktime += 1;
                MessageBox.Show("还没完成？那我先sleep" + marktime);

                Thread.Sleep(4000);

            }
        }
        private delegate int MyMethod();
        private int method()
        {
            Thread.Sleep(3000);
                   
            return 100;
        }  
        private void MethodCompleted(IAsyncResult asyncResult)
        {
            if (asyncResult == null) return;
            textBox1.Text = (asyncResult.AsyncState as MyMethod).EndInvoke(asyncResult).ToString();
          //MessageBox.Show((asyncResult.AsyncState as MyMethod).EndInvoke(asyncResult).ToString()); 
        }