C#

 

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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());

        }