using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Diagnostics;

using System.Linq;

​

namespace EventPerformaneMeasurement

{

    public class Program

    {

        public static void Main()

        {

            var sw = new Stopwatch();

            var mc = new MyClass();

            var list = Enumerable.Range(1, 15000).Select(x => new PropertyChangedEventHandler((s, _e) => { Console.WriteLine(string.Format("Handler {0} called", x)); })).ToList();

            sw.Restart();

           list.ForEach(handler=>mc.PropertyChangedNew += handler); 

            sw.Stop();

            Console.WriteLine(sw.ElapsedMilliseconds);

            sw.Restart();

            list.ForEach(handler=>mc.PropertyChangedNew -= handler); 

            sw.Stop();

            Console.WriteLine(sw.ElapsedMilliseconds);

        }

    }

​

    class MyClass

    {

        private HashSet<PropertyChangedEventHandler> _handlers = new HashSet<PropertyChangedEventHandler>();

        public event PropertyChangedEventHandler PropertyChangedNew

        {

            add {_handlers.Add(value);}

            remove {_handlers.Remove(value);}

        }

    }

}