Event when component added or removed

Hi,

Does anyone know of a runtime ability to listen for when a component is added or removed to a gameobject?

What would be nice:

gameobject.componentAdded += OnComponentAdded;
gameobject.componentRemoved += OnComponentAdded;

Mike

 

You cant by default. But you can write a wrapper around GetComponent, for example an extension or wrapper base class which you sololy use then which fires those events.

 

There is no such thing as removeComponent.

That said, you can just use OnAwake and OnDestroy for the add and 'remove' events.

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class TEST : MonoBehaviour {
5.    Rect AddButton, DeleteButton;
6.    int ID;
7.  
8.    void Awake () {
9.      ID = Random.Range( 0, 1000 );
10.      Debug.Log( "Component " + ID + " Awake (Added)" );
11.      AddButton = new Rect( Random.Range( 0, Screen.width - 50 ), Random.Range( 0, Screen.height - 50 ), 50, 50 );
12.      DeleteButton = new Rect( Random.Range( 0, Screen.width - 50 ), Random.Range( 0, Screen.height - 50 ), 50, 50 );
13.    }
14.  
15.    void OnDestroy () {
16.      Debug.Log( "Component " + ID + " Destroyed (Removed)" );
17.    }
18.  
19.    void OnGUI () {
20.      if ( GUI.Button( AddButton, "Add\n" + ID ) ) {
21.        gameObject.AddComponent<TEST>();
22.      }
23.  
24.      if ( GUI.Button( DeleteButton, "DEL\n" + ID ) ) {
25.        Destroy( this );
26.      }
27.    }
28. }

Of course, these will only fire from within the component that is added or removed, not from a watcher or similar.
But for that, you just call some code at the same time as adding or destroying the component from wherever that happens.

Code (CSharp):

1.     someObject.AddComponent<SomeThing>();
2.     DoAThing();
3.  
4.     Destroy(GetComponent<SomeThing>())
5.     DoAnotherThing();
6.  

If you wanted, you can make a manager object to handle both steps, then you just

Code (CSharp):

1.     ComponentManager.MyComponentAdder(targetGameObject, desiredComponentType)
2.