值参数不能加，引用参数可以。

引用参数是共享的

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace Delegate

{

    public delegate void Myfunction(int valCount,ref int refCount);

    class Program

    {

        static void Main(string[] args)

        {

            Myfunction mf = (Myfunction)MethodA + (Myfunction)MethodB + (Myfunction)MethodA;

            int valCount = 0;

            int refCount = 0;

            mf(valCount,ref refCount);

            //display 0;

            Console.WriteLine("valCount: "+valCount);

            //display 5;

            Console.WriteLine("refCount: "+refCount);

            Console.ReadLine();

        }

        public static void MethodA(int valCount, ref int refCount)

        {

            ++valCount;

            ++refCount;

        }

        public static void MethodB(int valCount, ref int refCount)

        {

            valCount += 3;

            refCount += 3;

        }

    }

}