using System;

//Define class as Publisher

public class Publisher

{

    //OnChange property containing all the 

    //list of subscribers callback methods

    public event Action OnChange = delegate { };

​

    public void RaiseChangeEvent()

    {

        //Invoke OnChange Action

        OnChange();

    }

}

public class Program

{

    public static void Main()

    {

         //Initialize publisher class object

        Publisher pub = new Publisher();

​

        //register for OnChange event - Subscriber 1

        pub.OnChange += () => Console.WriteLine("Subscriber 1 Called");

        //register for OnChange event - Subscriber 2

        pub.OnChange += () => Console.WriteLine("Subscriber 2 Called");

​

        //raise the event

        pub.RaiseChangeEvent();

​

        //After this RaiseChangeEvent() method is called

        //all subscribers callback methods will get invoked

        //and will print string mentioned inside it

    }

}