using System;

​

public static class Program

{

    public static void Main()

    {

        Item item = new Item(1,"Product1",254,10);

        Console.WriteLine("Enter the Stock in hand value");

        int val = Convert.ToInt32((Console.ReadLine()));            

        item.Stock_in_hand = val;

        Console.WriteLine(item.Stock_in_hand.ToString());

    }

}

​

public class Item

{

    int itemid; string name;int price; int stockinhand;

    public Order order;

    public int ItemID

    {

        get;set;

    }

    public int Stock_in_hand

    {

        get{return stockinhand;}

        set

        {

            if(value < 5)

            {

                order.RefillRequest += new EventHandler(RefillRequestHandler);

                order.InitiateRefillRequest();              

            }

            stockinhand = value;

        }

    }

    public int Price

    {

        get;set;

    }

    public string Name

    {

        get;set;

    }

    public Item(int id,string name,int price,int stockinhand)

    {

        this.order = new Order();

        this.ItemID = id;

        this.Name = name;

        this.Price = price;

        this.Stock_in_hand = stockinhand;

    }

    public void RefillRequestHandler(object sender, EventArgs e)

    {

        Console.WriteLine("Event triggered!!");

    }

}

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

​

public class Order

{

    public event EventHandler RefillRequest; 

    public Order()

    {

    }

    public void InitiateRefillRequest()

    {

        OnStockInHandReduced();

    }

    protected virtual void OnStockInHandReduced()

    {

        if(RefillRequest != null)

        RefillRequest.Invoke(this,null);

    }

    public void RefillRequestHandler(object sender, EventArgs e)

    {

        Console.WriteLine("Event triggered and code executed");

        Console.ReadLine();

    }

}

​