Subscribe to event

using System;
using System.Collections.Generic;
using System.Threading;

// Define a class to hold custom event info
public class CustomEventArgs : EventArgs
{
    public CustomEventArgs(string s)
    {
        info = s;
    }
    private string info;

    public string Info
    {
        get { return info; }
        set { info = value; }
    }
}

// Class that publishes an event
class Publisher
{

    //Event that using above class
    public event EventHandler<CustomEventArgs> RaiseCustomEvent;

    public void DoSomething()
    {
        // Write some code that does something useful here
        // then raise the event. You can also raise an event
        // before you execute a block of code.

        OnRaiseCustomEvent(new CustomEventArgs("Help!!!"));
        Thread.Sleep(2000);
        //recursion
        DoSomething();
    }

    // Wrap event invocations inside a protected virtual method
    // to allow derived classes to override the event invocation behavior
    protected virtual void OnRaiseCustomEvent(CustomEventArgs e)
    {
        // Make a temporary copy of the event to avoid possibility of
        // a race condition if the last subscriber unsubscribes
        // immediately after the null check and before the event is raised.
        EventHandler<CustomEventArgs> handler = RaiseCustomEvent;

        // Event will be null if there are no subscribers
        if (handler != null)
        {


            e.Info += String.Format(" at {0}", DateTime.Now.ToString());
            // Use the () operator to raise the event.
            handler(this, e);
        }
    }
}


class Subscriber
{
    private string id;
    public Subscriber(string ID, Publisher pub)
    {
        id = ID;
        // Subscribe to the event
        pub.RaiseCustomEvent += HandleCustomEvent;
    }

    // Define what actions to take when the event is raised.
    void HandleCustomEvent(object sender, CustomEventArgs e)
    {
        Console.Beep();
        Console.WriteLine("I caught the event!!!");
        Console.WriteLine(e.Info);
    }
}

class Program
{
    static void Main()
    {
        Publisher pub = new Publisher();
        Subscriber sub1 = new Subscriber("sub1", pub);

        // Call the method that raises the event.
        pub.DoSomething();
    }
}