Invoke & BeginInvoke 异步委托

有这么一句话，把方法传递给其他方法，需要使用委托。什么意思呢？

委托是方法的类型安全的引用。

参数倒知道，把参数传递给其他方法，这个方法传递给其他方法，是怎么回事呢？

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;

namespace DelegateStudyWell
{
    class Program
    {
        public delegate int TakesAWhileDelegate(int data, int ms);
        static void Main(string[] args)
        {
            //投票技术
            //TakesAWhileDelegate dl = TakesAWhile;
            //IAsyncResult ar = dl.BeginInvoke(1, 3000, null, null);

            //while (!ar.IsCompleted)
            //{
            //    Console.WriteLine(".");
            //    System.Threading.Thread.Sleep(50);
            //}
            //int result = dl.EndInvoke(ar);     //返回函数调用后的返回值
            //Console.WriteLine("result:{0}", result);
            //异步回调
            TakesAWhileDelegate dl = TakesAWhile;
            dl.BeginInvoke(1, 3000, TakesAWhileCompleted, dl);
            for (int i = 0; i < 100; i++)
            {
                Console.Write(".");
                System.Threading.Thread.Sleep(50);
            }





            Console.ReadLine();

        }
        static int TakesAWhile(int data, int ms)
        {
            Console.WriteLine("begin");
            System.Threading.Thread.Sleep(ms);
            Console.WriteLine("completed");
            return ++data;
        }
        static void TakesAWhileCompleted(IAsyncResult ar)
        {
            if (ar == null) throw new ArgumentNullException("ar");
            TakesAWhileDelegate dl = ar.AsyncState as TakesAWhileDelegate;
            int result = dl.EndInvoke(ar);
            Console.WriteLine("result:{0}", result);
        }


    }

}