How to use Delegates. Like a BOSS.

I decided to write another tutorial about one of the basics of unity programming: Delegates and Events.
I try to focus on the use cases and design decisions and not only the code aspect.

http://unitydojo.blogspot.com/2015/03/how-to-use-delegates-in-unity-like-boss.html

What do you think about it? Would you like to see more of this tutorials?

 

of course we do, thanks very much for great tutorials

 

Good one. I personally avoid the null check (and the potential bugs from forgetting it) like this
event SimpleDelegate OnTestEvent = delegate {};

You could also mention static events.

 

Thanks a lot Vectrex!

I didn't know that trick with the initialization of the delegates. The only problem I see there is in case you reset the delegate like this: "OnTestEvent = null;". But it's not really a problem because you should do that.

I already added your tips to the post!

 

Can you go into more detail?

 

Nice article. You can also use event Actions. It's an underlying delegate and is a bit cleaner in my opinion.

 

Simply when you define an event, stick an empty delegate at the end. A Bit messy looking but does the trick. Lots of forums discussions seems to indicate that it doesn't have a performance penalty.

public event ExampleDelegate OnExampleEvent = delegate {};

 

No!

Stop. Don't ever declare an empty delegate. It's bad practice. Null check it.

A problem will appear if you rely on this technique and then you have to serialize the class. You will eliminate the event, and then on deserialization you will get a NullRefference.... .So one can just stick to the "old way" of doing things. It's safer. It's better. It's the "RIGHT" way of doing it.

 

I've been pwned! Yeah that's an issue. Although the serialiser should add it
Really, I consider it a bug that you have to null check. It's an event, logically it shouldn't ever care if there's zero or a million listeners. The "UnityEvent" type lets you do this neater actually. I hope they expand the editor stuff for listeners subscribing themselves.

 

Thanks SubZeroGaming for making everything clearer!

It would be very hard to learn such things otherwise!

Post updated thanks to your comments

 

Thanks for the creds