CODEWITHSUNDEEP
c#eventsevent-handlingnullreferenceexception
Sweeper
Sweeper

Reputation: 273643

Is there a better way to initialize EventHandlers in C#

Let's say that I am writing a class library of some sort. I have a class:

public class PopupControl : UserControl {
    // Some code
    public event EventHandler PopupFinished;
}

If I want to handle this event in another class, I just use the += operator and nothing special happens. However, when the event is not handled anywhere, PopupFinished is null. And when I call PopupFinished (this, EventArgs.Empty), I get a NullReferenceException. So I need to do this:

public PopupControl () {
    PopupFinished += popupFinished;
    //Some more code
}

private void popupFinished (object sender, EventArgs e) {}

This doesn't sound like a good programming practice though. (or is it?)

Then I thought of another way:

try {
    PopupFinished (this, EventArgs.Empty);
} catch (NullReferenceException) {}

But that doesn't sound right either.

Please tell me which of the above is better and whether there is another way to do that. Thanks!

Upvotes: 2

Views: 70

Answers (1)

Krikor Ailanjian
Krikor Ailanjian

Reputation: 1852

Do a test to check PopupFinished is not null before calling it.

if(PopupFinished != null)
    PopupFinished();

Upvotes: 3

Related Questions