Should You Use Empty Anonymous Delegates in Event Declarations?

Empty Anonymous Delegates in Event Declarations: Potential Drawbacks

In event programming, the common practice of adding an empty anonymous delegate directly on event declaration, as seen below, simplifies event raising by eliminating the need for null checks:

// Deliberately empty subscriber
public event EventHandler AskQuestion = delegate {};

While this technique solves a specific issue, it's essential to consider potential drawbacks:

1. Performance Impact: Calling the empty delegate subscriber for every event invocation may introduce a negligible performance overhead. In high-frequency scenarios, this could accumulate.
2. Maintenance Overhead: While the intention of the empty delegate may be clear initially, it might not be self-explanatory over time. This could lead to maintenance headaches for developers unfamiliar with the pattern.

Instead of relying on empty delegates, an alternative approach is to leverage an extension method that handles null checks and simplifies event raising:

public static void Raise(this EventHandler handler, object sender, EventArgs e)
{
    if(handler != null)
    {
        handler(sender, e);
    }
}

Using this extension, event raising becomes effortless and reduces null-check overhead:

// Works, even for null events.
MyButtonClick.Raise(this, EventArgs.Empty);

This extension-based solution eliminates both the performance and maintenance drawbacks associated with anonymous empty delegates in event declarations.

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