Microsoft Certified Solutions Developer (MCSD) Certification Practice Test

How do you signal that an event has occurred?

1. By invoking the event handler directly

2. By raising the event through the class

3. By assigning a value to the event

4. By notifying all subscribers immediately

The correct answer is: By raising the event through the class

Raising the event through the class is the correct approach to signal that an event has occurred. In object-oriented programming, events are a way to provide notifications about occurrences or changes in state within an object. An event is typically defined within a class, and when it occurs, the class invokes the event, thereby notifying all registered subscribers. This process involves defining a delegate that matches the signature of the event handler methods, and then using the event keyword in conjunction with the delegate to create an event. When the event is raised, it allows any subscribed event handlers to be invoked, enabling them to respond to the event appropriately. In contrast to this correct approach, invoking the event handler directly would bypass the event mechanism, preventing other subscribers from being notified. Assigning a value to the event doesn’t make sense in most event-driven programming models since events represent actions rather than values. Notifying all subscribers immediately could lead to inefficiencies and a tightly coupled design, which goes against the idea of decoupling senders and receivers of notifications that events promote. Thus, raising the event within the class effectively handles the signaling of events and maintains proper design principles.