Maha

Maha

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NP114 Moving delagate type

Aug 6 2008 11:41 AM

Hi Guys

 

NP114 Moving delagate type

 

Following program is executing well. For curiosity I have moved public delegate void MeltdownHandler(object reactor, MeltdownEventArgs myMEA); to a different place from it’s original position (Original position is highlighted in yellow. New position is highlighted in blue).

 

But after moving program is not executing. Please explain the reason. How can it be altered to execuate after moving delagate type to the new position.    

 

Thank you

 

using System;

 

public delegate void MeltdownHandler(object reactor, MeltdownEventArgs myMEA);

 

// declare the MeltdownEventArgs class (implements EventArgs)

class MeltdownEventArgs : EventArgs

{

    // declare a private field named message

    private string message;

 

    // define a constructor

    public MeltdownEventArgs(string message)

    {

        this.message = message;

    }

 

    // define a property to get the message

    public string Message

    {

        get

        {

            return message;

        }

    }

}

 

// declare the Reactor class

class Reactor

{

    // declare a private field named temperature

    private int temperature;

 

    // declare a delegate class named MeltdownHandler

    //public delegate void MeltdownHandler(object reactor, MeltdownEventArgs myMEA);

 

    // declare an event named OnMeltdown

    public event MeltdownHandler OnMeltdown;

 

    // define a property to set the temperature

    public int Temperature

    {

        set

        {

            temperature = value;

 

            // if the temperature is too high, the reactor melts down

            if (temperature > 1000)

            {

                MeltdownEventArgs myMEA =

                  new MeltdownEventArgs("Reactor meltdown in progress!");

                OnMeltdown(this, myMEA);

            }

        }

    }

}

 

// declare the ReactorMonitor class

class ReactorMonitor

{

    // define a constructor

    public ReactorMonitor(Reactor myReactor)

    {

        myReactor.OnMeltdown += new Reactor.MeltdownHandler(DisplayMessage);

    }

 

    // define the DisplayMessage() method

    public void DisplayMessage(object myReactor, MeltdownEventArgs myMEA)

    {

        Console.WriteLine(myMEA.Message);

    }

}

 

public class Example12_4

{

    public static void Main()

    {

        // create a Reactor object

        Reactor myReactor = new Reactor();

 

        // create a ReactorMonitor object

        ReactorMonitor myReactorMonitor = new ReactorMonitor(myReactor);

 

        // set myReactor.Temperature to 100 degrees Centigrade

        Console.WriteLine("Setting reactor temperature to 100 degrees Centigrade");

        myReactor.Temperature = 100;

 

        // set myReactor.Temperature to 500 degrees Centigrade

        Console.WriteLine("Setting reactor temperature to 500 degrees Centigrade");

        myReactor.Temperature = 500;

 

        // set myReactor.Temperature to 2000 degrees Centigrade

        // (this causes the reactor to meltdown)

        Console.WriteLine("Setting reactor temperature to 2000 degrees Centigrade");

        myReactor.Temperature = 2000;

 

    }

}

/*

Setting reactor temperature to 100 degrees Centigrade

Setting reactor temperature to 500 degrees Centigrade

Setting reactor temperature to 2000 degrees Centigrade

Reactor meltdown in progress!

*/

 


Answers (11)