How do I have an object notify me of any changes in real time?

Events provide a generally useful way for objects to signal state changes that may be useful to clients of that object. In order to support this, you need to create an event of type EventHandler with the name <property name>Changed. Then, in the property setter of the object, after you store the value (or do whatever you have to do to ensure that getting the value will return the new value), fire the event.

The event model in the .NET Framework is based on having an event delegate that connects an event with its handler. To raise an event, two elements are needed:

• A class that holds the event data.
• This class must derive from the base class EventArgs.

A delegate that points to a method that provides the response to the event.

Example:

public delegate void EventHandler(Object sender, EventArgs e);
public event EventHandler DataChangedEventHandler;

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