using System;

using System.Linq;

using System.Collections;

using System.Collections.Generic;

using System.Reflection;

​

//https://www.c-sharpcorner.com/article/aspect-oriented-programming-in-c-sharp-using-dispatchproxy/

public class Program

{

    public static void Main()

    {

        var foo = new  Foo();

        var decoratedFoo = AspectDecorator<IFoo>.Create(foo);

        Console.WriteLine("\n\nClass:\n");

        foo.method1();

        foo.method2();

        foo.method3();

        Console.WriteLine("\n\nDecorated Class:\n");

        decoratedFoo.method1();

        decoratedFoo.method2();

        decoratedFoo.method3();

    }

​

}

public class Foo : IFoo{

        public void method1(){Console.WriteLine("> call method1");}

        public void method2(){Console.WriteLine("> call method2");}

        public void method3(){Console.WriteLine("> call method3");}

}

public interface IFoo{

    void method1();

    void method2();

    void method3(); 

}

public class AspectDecorator<T> : DispatchProxy 

{

    private T _impl;

    protected override object Invoke(MethodInfo targetMethod, object[] args)

    {

        Console.WriteLine($"Before : {targetMethod.Name}");

        var obj =  _impl.GetType().GetMethod(targetMethod.Name).Invoke(_impl, args);

        Console.WriteLine($"After : {targetMethod.Name}");

        return obj;

    }

    public void SetTarget(T target)

    {

        this._impl = target;

    }

    public static T Create(T decorated)

    {

        object proxy = Create<T, AspectDecorator<T>>();

        ((AspectDecorator<T>) proxy)._impl=decorated;

        return (T)proxy;

    }

​

​

}