定义申明

public interface MyInterface
    {
        void Do();
        int Add(int x, int y);
    }

实现申明

using System;

 public class MyImplement : MyInterface
    {
        public int Add(int x, int y)
        {
            Console.WriteLine("执行Add");
            return x + y;
        }

        public void Do()
        {
            Console.WriteLine("执行Do");
        }
    }

定义代理应该含有的东西

public interface IProxy
    {
        object ImplementInstance { get; set; }
    }

实现代理

using System;
using System.Reflection;

public class MyProxy : DispatchProxy, IProxy
    {
        public object ImplementInstance { get; set; }

        public TInterface CreateProxy<TInterface, TImplement>()
            where TImplement : class, TInterface, new()
        {
            return this.CreateProxy<TInterface, TImplement, MyProxy>();
        }

        public TInterface CreateProxy<TInterface, TImplement, TProxy>()
            where TProxy : DispatchProxy, IProxy
            where TImplement : class, TInterface, new()
        {
            return this.CreateProxy<TInterface, TImplement, TProxy>(Activator.CreateInstance<TImplement>());
        }

        public TInterface CreateProxy<TInterface, TImplement, TProxy>(TImplement implement)
            where TProxy : DispatchProxy, IProxy
            where TImplement : class, TInterface
        {
            TInterface @interface = DispatchProxy.Create<TInterface, TProxy>();
            (@interface as IProxy).ImplementInstance = implement;
            return @interface;
        }

        protected override object Invoke(MethodInfo targetMethod, object[] args)
        {
            Console.WriteLine("执行前");
            object result = targetMethod.Invoke(this.ImplementInstance, args);
            Console.WriteLine("执行后");

            return result;
        }
    }

使用动态代理

class Program
    {
        static void Main(string[] args)
        {
            MyProxy myProxy = new MyProxy();
            MyInterface myInterface = myProxy.CreateProxy<MyInterface, MyImplement>();
            myInterface.Do();
            int z = myInterface.Add(1, 1);
        }
    }