Skipping Null Checks on Events

Yesterday I learned a neat C# trick that can be used to skip the traditional null check associated with defining, then firing events:

public class MyClassWithAnEvent
{
    public event EventHandler MyEvent;

    protected void FireMyEvent()
    {
        if (MyEvent != null)
            MyEvent(this, EventArgs.Empty);
    }
}

By immediately assigning the event with an empty event handler, we can guarantee that the event is never null, thereby saving us a line of code whenever we call it:

public class MyClassWithAnEvent
{
    public event EventHandler MyEvent = (o, e) => {};

    protected void FireMyEvent()
    {
        MyEvent(this, EventArgs.Empty);
    }
}

Posted on October 20, 2010 from Calgary

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My name is Brandur. I'm a polyglot software engineer and part-time designer working at Heroku in San Francisco, California. I'm a Canadian expat. My name is Icelandic. Drop me a line at brandur@mutelight.org.

Aside from technology, I'm interested in energy and how it relates to our society, travel, longboarding, muay thai, symphonic metal, and the guitar.

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