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TypeScript : events in c# geeksforgeeks


// C# program to illustrate the use of Delegates 
using System; 
namespace GeeksForGeeks { 
// declare class "Geeks" 
class Geeks { 
// Declaring the delegates 
// Here return type and parameter type should  
// be same as the return type and parameter type 
// of the two methods 
// "addnum" and "subnum" are two delegate names 
public delegate void addnum(int a, int b); 
public delegate void subnum(int a, int b); 
    // method "sum" 
    public void sum(int a, int b) 
        Console.WriteLine("(100 + 40) = {0}", a + b); 
    // method "subtract" 
    public void subtract(int a, int b) 
        Console.WriteLine("(100 - 60) = {0}", a - b); 
// Main Method 
public static void Main(String []args) 
    // creating object "obj" of class "Geeks" 
    Geeks obj = new Geeks(); 
    // creating object of delegate, name as "del_obj1"  
    // for method "sum" and "del_obj2" for method "subtract" & 
    // pass the parameter as the two methods by class object "obj" 
    // instantiating the delegates 
    addnum del_obj1 = new addnum(obj.sum); 
    subnum del_obj2 = new subnum(obj.subtract); 
    // pass the values to the methods by delegate object 
    del_obj1(100, 40); 
    del_obj2(100, 60); 
    // These can be written as using 
    // "Invoke" method 
    // del_obj1.Invoke(100, 40); 
    // del_obj2.Invoke(100, 60); 
//1. (Optionally) Make a event class to return data in. Microsoft has a EventArgs class you can derive from, but benifits are minimal besides ahereance to standards.
//2. Make a event class 2 sub scribe to or that will publish the event.
//3. In any place you wish to use the event (subscribe to the event) or subscribe to the event.
    /// 1. An event argument to handle the Data received
    public class YourEventReceiveEventArgs : EventArgs
    	//give out any properties you wish the subscriber to have here.
		//often makeing the set private so the event can be secure is a good idea.
        public byte[] YourDataAsProperties { get; private set; }
        public DateTime DateTime { get; private set; } = DateTime.UtcNow;
        internal DataReceiveEventArgs(byte[] Data){ this.Data = Data; }
	//2. In the Class that will be raise (creates and orignates from) the event add a delegate EventHandler
	public class YourEventPublishingClass
      	//Create a delegate of the signiture of methods you would like to subscribe the event to
      	//Optionally: The object is sender is optional but is a ahereance to standards.
      	//Optionally: Add the event class that you would like to pass data in
		public delegate void YourEventHandler(object Sender, DataReceiveEventArgs e);
		//create Your event using your newly created signature.
    	public event YourEventHandler YourEvent;
      	//Create a way to raise your event this could be a call to check
      	//something durring another in anthor thread or async watch method.
		protected void RaseEvent()
          //if(Condtions are met)
          	handler?.Invoke(this, e);
	//3. Subscribe to event and attach a method to rase on the event
	private class YourSubscriberClass
		//using instance of the class (or you could have a static style class in some rare cases) subscribe
      	//note how you instance and pass the class is up to you.
		private YourEventPublishingClass YourEventPublishingClassProperty;
      	public YourSubscriberClass(YourEventPublishingClass EventClassIn)
      	   YourEventPublishingClassProperty = EventClassIn;
           YourEventPublishingClassProperty.YourEvent += YourEventRecivedMethodEvent;
		//Make sure you your event follows the signature of your delagate
    	private void YourEventRecivedMethodEvent(object Sender, YourEventReceiveEventArgs e)
      		//replace this with your code
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks; namespace event_programming{    //This is Subscriber Class    class Program    {        static void Main(string[] args)        {            AddTwoNumbers a = new AddTwoNumbers();            //Event gets binded with delegates            a.ev_OddNumber += new AddTwoNumbers.dg_OddNumber(EventMessage);            a.Add();            Console.Read();        }              //Delegates calls this method when event raised.          static void EventMessage()        {            Console.WriteLine("********Event Executed : This is Odd Number**********");        }    }    //This is Publisher Class    class AddTwoNumbers    {                public delegate void dg_OddNumber(); //Declared Delegate             public event dg_OddNumber ev_OddNumber; //Declared Events         public void Add()        {            int result;            result = 5 + 4;            Console.WriteLine(result.ToString());            //Check if result is odd number then raise event            if((result % 2 != 0) && (ev_OddNumber != null))            {                ev_OddNumber(); //Raised Event            }                  }    }}
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