Delegate based Events

a delegate is nothing more than a type safe method reference,

public delegate void NumberChangedEventHandler(int number)

This delegate can be used to call any method with a matching signature, the name of method and the name of parameter are not important, but you have to have the same signature.

Here is example:

public delegate void NumberChangedEventHander(int number);

public class MyPublisher
{
public NumberChangedEventHander NumberChanged;
}
public class MySubscriber : Page
{
public void OnNumberChanged(int number)
{
string mes = "New value is " + number ;
}
}


UI call the delegate:

MyPublisher publisher = new MyPublisher();
MySubscriber subscriber1 = new MySubscriber();
MySubscriber subscriber2 = new MySubscriber();
publisher.NumberChanged += new NumberChangedEventHander(subscriber1.OnNumberChanged);
publisher.NumberChanged += new NumberChangedEventHander(subscriber2.OnNumberChanged);
publisher.NumberChanged(3);