What is the difference between delegate and event in C#?

Question

Accepted Answer

**Delegate** — type-safe function pointer. **Event** — mechanism for notifications.

**Delegate:**
- Type-safe function pointer.
- Can point to one or more methods.
- Can be invoked directly.

```csharp
// Define delegate
public delegate void NotifyHandler(string message);

// Use delegate
public class Publisher {
    public NotifyHandler OnNotify;

public void DoSomething() {
        OnNotify?.Invoke("Done!");
    }
}
```

**Event:**
- Wrapper around delegate.
- Only class can invoke (encapsulation).
- Subscribers can only add/remove handlers.

```csharp
public class Publisher {
    // Event
    public event NotifyHandler OnNotify;

public void DoSomething() {
        OnNotify?.Invoke("Done!");  // OK — same class
    }
}

public class Subscriber {
    public void Subscribe(Publisher p) {
        p.OnNotify += HandleNotify;  // OK — subscribe
        p.OnNotify?.Invoke("Hi");    // Error! Cannot invoke
    }
}
```

**Key differences:**
- **Delegate** — can invoke directly.
- **Event** — only owner can invoke.
- **Event** — better encapsulation.

C#: What is the difference between delegate and event in C#?