异步Async

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading;
using System.Windows.Forms;

namespace 异步Async
{
    /*
     * 1.同步启动时会卡主界面，异步不会，原因是异步调用了子线程去执行，使主线程得到释放
     * 2.同步方法慢,异步方法快,启动多线程,占用更多资源
     * 3.异步是无序的
     */
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        
        private Action<string> act; //定义一个无返回结果委托
        private Func<string, long> func; //定义一个有返回结果委托

        /// <summary>
        /// 异步调用
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnAsync_Click(object sender, EventArgs e)
        {
            //act = t => Console.WriteLine("别跟我BB,{0},当前线程是{1}",t,Thread.CurrentThread.ManagedThreadId);
            //act.BeginInvoke("你大爷还是你大爷",null,null);

            //将DoSomething方法执行5次
            Console.WriteLine("*****************异步方法btnAsync_Click****************");
            
            for (int i = 0; i < 5; i++)
            {
                act = DoSomething; //需要结合委托使用
                act.BeginInvoke("异步", null, null); //异步启动多个线程调用DoSomething()方法
                //第一个参数为DoSomething()方法的name参数，第二为回调函数，第三为回调函数的状态参数
            }
            Console.WriteLine("*****************异步方法btnAsync_Click****************");
            Console.WriteLine("
");
        }

        /// <summary>
        /// 异步进阶
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnAsyncAdvanced_Click(object sender, EventArgs e)
        {
            Console.WriteLine("*****************异步进阶btnAsync_Click****************");
            act = DoSomething; 

            AsyncCallback back = t => Console.WriteLine("这里是回调函数,当前线程ID是{0},AsyncState为{1}",Thread.CurrentThread.ManagedThreadId,t.AsyncState);

            IAsyncResult result= act.BeginInvoke("异步回调", back, "回调参数param思密达"); //异步回调,添加回调参数

            /*
            //异步等待1
            result.AsyncWaitHandle.WaitOne(-1); //主线程无限期等待子线程结束,相当于回到同步

            //异步等待2,可以做进度条
            while (!result.IsCompleted)
            {
                Thread.Sleep(100);
                Console.WriteLine("请继续等待.......");
            }

            //异步等待3
            act.EndInvoke(result);
            */

            Console.WriteLine("*****************异步进阶btnAsync_Click****************");
            Console.WriteLine("
");
        }

        /// <summary>
        /// 异步进阶2,调用有返回结果的方法
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnAsyncAdv2_Click(object sender, EventArgs e)
        {
            Console.WriteLine("*****************异步进阶2btnAsync_Click****************");
            func = GetDoSomething;

            /*第一种异步等待等到该GetDoSomething()方法的返回结果,但是会卡住主线程

             IAsyncResult result = func.BeginInvoke("异步进阶2", t =>Console.WriteLine("这里是回调函数,当前线程ID是{0},AsyncState为{1}", Thread.CurrentThread.ManagedThreadId, t.AsyncState), "哈哈哈param");


             在等待的过程中可以做别的很多事........
             这里可以调用其它方法


            long r = func.EndInvoke(result);
            Console.WriteLine("sum的结果为:{0}",r);

            */

            //第二种异步等待结果，直接将等待方法EndInvoke()写入回调函数中,注:拉姆达表达式的匿名函数可以写成 new AsyncCallback(回调函数名),该函数需加参数(IAsyncResult result)

            //注：t为得到的result，第二种的好处是不会卡住主线程，因为异步等待在子线程中运行
            IAsyncResult result = func.BeginInvoke("异步进阶2", t =>
            {
                Console.WriteLine("这里是回调函数,当前线程ID是{0},AsyncState为{1}", Thread.CurrentThread.ManagedThreadId, t.AsyncState);

                //在这里直接得到GetDoSomething()方法的返回结果，6不6
                long r = func.EndInvoke(t);
                Console.WriteLine("sum的结果为:{0}",r);
            }, "哈哈哈param");


            //下面在等待过程中可以做别的很多事.......
            //可以调用其它方法,如:
            Console.WriteLine("这里可以做别的事儿......");
              

            Console.WriteLine("*****************异步进阶2btnAsync_Click****************");
        }

        /// <summary>
        /// 同步调用
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnSync_Click(object sender, EventArgs e)
        {
            //将DoSomething执行5次
            Console.WriteLine("*****************同步方法btnSync_Click****************");
            for (int i = 0; i < 5; i++)
            {
                DoSomething("同步");
            }
            Console.WriteLine("*****************同步方法btnSync_Click****************");
            Console.WriteLine("
");
        }

        /// <summary>
        /// 耗时void无返回结果方法
        /// </summary>
        /// <param name="name"></param>
        private void DoSomething(string name)
        {
            //监控此方法所用时间
            Stopwatch watch = new Stopwatch();
            watch.Start();
            Console.WriteLine("当前是{0}在调用次方法,当前线程ID是{1}",name,Thread.CurrentThread.ManagedThreadId);
            long sum = 0;
            for (int i = 0; i < 1000000000; i++)
            {
                sum += i;
            }
            Thread.Sleep(1000); //等待1秒
            watch.Stop();
            Console.WriteLine("sum结果是：{0},耗时{1}", sum, watch.ElapsedMilliseconds);
        }

        /// <summary>
        /// 有返回结果的方法
        /// </summary>
        /// <param name="name"></param>
        /// <returns></returns>
        private long GetDoSomething(string name)
        {
            long sum = 0;
            for (int i = 0; i < 1000000000; i++)
            {
                sum += i;
            }
            return sum;
        }
    }
}