Events

One common use of a delegate is to register methods to be executed when an event occurs.

The namespace System declares the delegate:

delegate void EventHandler(object sender, EventArgs e);

The class Button has a field called Click:
```
public event EventHandler Click;
```
Suppose we declare an instance of the class Button:
```
private Button iAddButton = new Button();
```
A method can be added to this Button's Click field using:
```
iAddButton.Click += new EventHandler(iHandleClick);
```
Add the keyword event to the declaration of a delegate to restrict access to the delegate.

This assumes the existence of the method:

protected void iHandleClick(object sender, EventArgs e)
{
    ...
}