using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading;

using System.Threading.Tasks;

using System.Windows.Forms;

namespace AsyncCallbackDemo

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

            objMyCal = ExecuteTask;

        }

        //定义一个委托

        public delegate int MyCalculator(int num,int ms);

        //根据委托定义方法，返回一个数的平方

        private int ExecuteTask(int num,int ms)

        {

            Thread.Sleep(ms);

            return num * num;

        }

        MyCalculator objMyCal = null;

        private void button1_Click(object sender, EventArgs e)

        {

            for (int i = 0; i < 11; i++)

            {

                //定义回调函数MyCallBack，传入回调值i

                objMyCal.BeginInvoke(10 * i,1000*1, MyCallBack, i);

            }

        }

        private void MyCallBack(IAsyncResult result)

        {

            //返回结果

            int res = objMyCal.EndInvoke(result);

            Console.WriteLine("第{0}个计算结果为{1}",result.AsyncState.ToString(),res);

        }

    }

}