C# 委托

1、委托的异步调用

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

namespace _04_委托的异步调用
{
    delegate string DelTest(string name);
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            this.Text = "";
        }
        DelTest del;
        private void button1_Click(object sender, EventArgs e)
        {
            del= Test;
            del += Test;
            //委托的异步调用
           IAsyncResult ir =  del.BeginInvoke("abc",Callback,null);

           //while (!ir.IsCompleted)
           //{
           //    this.Text += "*";
           //    System.Threading.Thread.Sleep(300);
           //}
            MessageBox.Show("Test");
        }

        void Callback(IAsyncResult ir)
        {
            //接收BeginInvoke 传过来的最后一个参数
            //ir.AsyncState
            string t = del.EndInvoke(ir);
            MessageBox.Show(t);
            MessageBox.Show("over");
        }

        string Test(string name)
        {
            for (int i = 0; i < 10000; i++)
            {
                Console.WriteLine(i);
            }
            return name;
        }
    }
}

2、委托

 public delegate int DelCompare(object o1,object o2);
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            object[] array = {"abc","ab","aaaaaaaa","abcde","a" };

            object o = GetMax(array, CompareString);

            MessageBox.Show(o.ToString());
        }

        private int CompareString(object o1, object o2)
        {
            string s1 = o1.ToString();
            string s2 = o2.ToString();
            return s1.Length - s2.Length;
        }

        public object GetMax(object[] array,DelCompare del)
        {
            object max = array[0];
            for (int i = 1; i < array.Length; i++)
            {
                if (del(max,array[i]) < 0)
                {
                    max = array[i];
                }
            }
            return max;
        }
      

 3、委托详解

public class BubbleSort
    {
        public delegate int  MyDelegate(int a);
//声明一个返回int 类型的传入参数为int的委托函数
        
        static void Main(string[] arg)
        {
            MyDelegate dele1, dele2;
            dele1 = new MyDelegate(JiSuan.getNum);//初始化委托
            dele2 = new MyDelegate(JiSuan.getNum2);
            var m = dele1(1);
            var n = dele1(1) + dele2(1);
        }
        
    }

    public class JiSuan
    {
        public static int getNum(int a)
        {
            return 3;
        }
        public static int getNum2(int a)
        {
            return 6;
        }
    }

委托的加减乘除运算

http://www.bubuko.com/infodetail-1450934.html

 public class BubbleSort
    {
        public delegate int  MyDelegate(int a,int b);
        
        static void Main(string[] arg)
        {
            var m=GetCaozuo()(9,3);
            
        }

        private static MyDelegate GetCaozuo()
        {
            return JiSuan.jia;
        }
        
    }

    public class JiSuan
    {
        public static int jia(int a, int b)
        {
            return a + b;
        }
        public static int jian(int a, int b)
        {
            return a -b;
        }
        public static int cheng(int a, int b)
        {
            return a * b;
        }
        public static int chu(int a, int b)
        {
            return a / b;
        }
    }

委托方法的加减 用于顺序执行

dele = JiSuan.jia;

dele += JiSuan.jian;

dele += JiSuan.cheng;
dele += JiSuan.chu;