What is the purpose of using myevent(this,EventArgs.Empty)?

Question

I am currently learning about delegates and events in csharp.I have the following set of codes:

using System;
using System.Collections.Generic;
using System.Text;

public delegate void mydel(object sender, EventArgs e); 

class event1
{
    public event mydel myevent;

    public void onfive()
    {
        Console.WriteLine("I am onfive event");
        Console.ReadKey();
        if (myevent != null)
        { 
            myevent(this,EventArgs.Empty);
        }
    }
}

public class test
{
    public static void Main()
    {
        event1 e1 = new event1();
        e1.myevent += new mydel(fun1);

        Random ran = new Random();
        for (int i = 0; i < 10; i++)
        {
            int rn = ran.Next(6); 
            Console.WriteLine(rn);
            Console.ReadKey();

            if (rn == 5)
            {
                e1.onfive(); 
            }
        }
    }

    public static void fun1(object sender, EventArgs e)
    {
        Console.WriteLine(" i am surplus function called due to use of '+=' ");
        Console.ReadKey();
    }
}

Whenever i put the following lines in comment the fun1() function is not called.Why it it so?

if (myevent != null)
 { 
  myevent(this,EventArgs.Empty);
 }

what is the purpose of these lines?

Answer 1

EventArgs : The EventArgs are arguments that the implementor of this event may find useful. With OnClick it contains nothing good, but in some events, like say in a GridView 'SelectedIndexChanged', it will contain the new index, or some other useful data.

EventArgs.Empty: Used to Pass the value to event handlers that are associated with events that do not have data.

Your event is of type mydel.

public mydel myevent; // declaring an event of type mydel with signature void mydel()

Hope this might give you some spark.

Answer 2

   if (myevent != null) //Checks so you instantiated a event
   { 
        myevent(this,EventArgs.Empty); // {this} will be equal to the sender in delegete myDel, {EventArgs.Empty} is since you are not passing any arguments to your delegate. 
   }