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

namespace test
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public delegate void MyDelegate();

        public MyDelegate mydelgate;

        public event MyDelegate EventMyDelegate;

        //事件触发机制(必须和事件在同一个类中) 外界无法直接用EventMyDel()来触发事件
        public void DoEventMyDelegate()
        {
            EventMyDelegate();
        }

        public void Fun_A()
        {
            MessageBox.Show("A方法触发了");
        }

        public void Fun_B()
        {
            MessageBox.Show("B方法触发了");
        }
        public void Fun_C()
        {
            MessageBox.Show("C方法触发了");
        }




        private void button1_Click(object sender, EventArgs e)
        {
            mydelgate();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            mydelgate = new MyDelegate(Fun_A);
            //mydelgate += Fun_A;
            mydelgate += Fun_B;

            EventMyDelegate += Fun_A; EventMyDelegate += Fun_B;
        }

        private void button2_Click(object sender, EventArgs e)
        {
            mydelgate = null;
            mydelgate += Fun_C;
        }

        private void button3_Click(object sender, EventArgs e)
        {
            DoEventMyDelegate();
        }

        private void button4_Click(object sender, EventArgs e)
        {
            EventMyDelegate = null;

<span style="white-space:pre">	</span>}

}

}

上面的代码，其中EventMyDelegate=null;这行代码在编译的时候并不会报错,但是以前在一个帖子里看过，说事件Event的没法对事件用赋值[=]号来进行注册，这就避免了破坏直接委托链的指针指向了。

我的编译器是VS2013，难道语法改了？