Observer Mode (Observer) delegate (delegate) C # simple Example

Observer Mode (Observer) delegate (delegate) C # simple Example

A few key points: the pattern makes the dependency between the target and the observation both loosely coupled and the notification automatically propagated
Example: A series of changes occurred after the player hit the enemy: After the explosion, the enemy less than 1 ....

namespace adapterpattern{public partial class Observerdelegateform:form {public Observerdelegateform ()            {InitializeComponent ();        Basedata.enemynumber = 100;  private void Btndisplay_click (object sender, EventArgs e) {explosionevent explosionevent = new            Explosionevent ();//Observer 1 Enemy Enemy = new Enemy ();//Observer 2 player P1 = new Player1 (); P1. Update + = new EventHandler (Explosionevent.explosionmax);//delegate to join Observer 1 P1. Update + = new EventHandler (enemy. decrease);//delegate added Observer 2 LISTBOX1.ITEMS.ADD (P1.        Display ());        }} public static class basedata//data broker {public static string displaystring {get; set;}    public static int Enemynumber {get; set;}  public delegate void EventHandler ();//delegate public for event handlers abstract class player {public event EventHandler      update;//declaring an event update protected virtual void Notify ()//Notification of join event execution  {if (update! = NULL) {update ();    }} public abstract string Display ();            public class Player1:player {public override string Display () {Notify ();//notify the Observer;        return basedata.displaystring + BaseData.EnemyNumber.ToString (); }} public class Explosionevent//Observer 1 {public void Explosionmax () {basedata.displays        Tring = "show Big Bang";          } public void Explosionmin () {basedata.displaystring = "show small explosions";    }        //.....    }       public class Enemy//Observer 2 {public void decrease () {basedata.enemynumber-= 1;         "The number of enemies decreased by 1"; }        //.....    }}

Observer Mode (Observer) delegate (delegate) C # simple Example