Delegates throws error when no observers present

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In my game, whenever a certain delegate is called a NullReferenceException is thrown if there are no observers yet instantiated. I realise a try-catch statement could fix t$$anonymous$$s, but why would it get thrown? Could it just not use the method anywhere?

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Answer by sacredgeometry · Aug 10, 2019 at 11:55 AM

You can null check it before calling it. If you want a clean syntax try the null propagation syntax.

https://davefancher.com/2014/08/14/c-6-0-null-propagation-operator/

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Ironstone · Aug 10, 2019 at 12:09 PM 0

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There's not really a code sample - just a call of 'troopAddObservers(e as Troop)' that causes a NullReferenceException. Which code would you like? It works with a simple try-catch anyway.

sacredgeometry Ironstone · Aug 10, 2019 at 12:12 PM 0

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Well that could be calling a null reference exception in a few places.

Do me a favour. Move the cast above the method call and debug its value:

 var troop = e as Troop;
 Debug.Log(troop);

If it's null, then thats your cause if not its probably as I said.

Try/ Catch/ Finally blocks are for exception handling not just for consuming exceptions. haha

It will stop it falling over but it doesn't fix the problem.

Ironstone sacredgeometry · Aug 10, 2019 at 12:14 PM 0

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It's not null, it's as you said :). Thanks!

Ironstone · Aug 10, 2019 at 12:13 PM 1

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Null Propagation syntax worked great, thanks a ton!

sacredgeometry Ironstone · Aug 10, 2019 at 12:13 PM 0

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You are very welcome.

Delegates throws error when no observers present

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