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Question by kynine · Dec 10, 2021 at 12:53 PM · c#unity 2dgetcomponentgetcomponents

GetComponents() returns null while GetComponent() returns non-null. WHY

Hello,

I am new to Unity and trying to get all Collider2D object in a script by gameObject.GetComponents(typeof(Collider2D)) but it returns null. I replaced GetComponents() with GetComponent() and it returns a Collider2D object.


To make a problem clear, I wrote the below script and it stops at later assertion statement.

Collider2D[] colliders = this.gameObject.GetComponents(typeof(Collider2D)) as Collider2D[]; Collider2D collider = this.gameObject.GetComponent(typeof(Collider2D)) as Collider2D; Assert.IsTrue(collider != null); Assert.IsTrue(colliders != null);


What causes this?


Here is my environment:

  • Unity Version - 2020.3.24f1 Personal

  • OS Version - Windows 10 20H2 (OS BUILD 19042.1348)


Thank you.

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Answer by andrew-lukasik · Dec 10, 2021 at 01:51 PM


>> gameObject.GetComponents returns null
This is not true. gameObject.GetComponents<Collider2D>() never returns null. Even where there are no components found. What has happened is you casted a Component[] to Collider2D[] and this is what returned you a null.

 // don't  believe me?
 var colliders = gameObject.GetComponents<Collider2D>();
 if( colliders==null )
     Debug.Log("You were right! :T wat...");
 else
     Debug.Log("I told you so");


Long story short: don't cast arrays in c#

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