Delegates vs Events in C#: Key Differences Every Developer Should Know
Delegates are type-safe function pointers in C# that hold references to one or more methods. Events are a special wrapper around delegates that enforce a publisher-subscriber pattern, ensuring only the owning class can raise the notification.
Developers mix them up because every Event needs a Delegate under the hood, making them look like the same thing. Imagine a nightclub: the Delegate is the guest list, the Event is the bouncer who decides who gets in and when.
Key Differences
Delegates can be declared public, invoked anywhere, and can return values. Events can only be invoked by the declaring type, must be void, and protect the list from outside tampering.
Which One Should You Choose?
Use a Delegate when you need a callback that can be called by any consumer. Choose an Event when you’re broadcasting “something happened” and want strict control over who can trigger it.
Examples and Daily Life
A Button.Click is an Event—you can’t force-click it from another class. A custom sort function passed into a List.Sort method is a Delegate—anyone can supply their own logic.
Can I assign null to an Event?
Yes, but only inside the class that declared it; outside code can only add or remove handlers.
Do Events always require the “EventArgs” pattern?
No, but it’s the .NET convention; using it keeps your code consistent and tooling-friendly.