Question

In Unity csharp, I want to make a GetOrAddComponent method, which will simplify the respectives GetComponent and AddComponent (for no good reason I suppose).

The usual way is this:

// this is just for illustrating a context
using UnityEngine;
class whatever : MonoBehavior {
public Transform child;
void whateverMethod () {

    BoxCollider boxCollider = child.GetComponent<BoxCollider>();
    if (boxCollider == null) {
        boxCollider = child.gameObject.AddComponent<BoxCollider>();
    }

}}

Right now I could make this class . . . :

public class MyMonoBehaviour : MonoBehaviour {

    static public Component GetOrAddComponent (Transform child, System.Type type) {
        Component result = child.GetComponent(type);
        if (result == null) {
            result = child.gameObject.AddComponent(type);
        }
        return result;
    }

}

. . . So this works:

// class whatever : MyMonoBehavior {

BoxCollider boxCollider = GetOrAddComponent(child, typeof(BoxCollider)) as BoxCollider;

But I wish I could write it like this:

BoxCollider boxCollider = child.GetOrAddComponent<BoxCollider>();

The only idea I could come up with would be way too complicated to do it (replacing each Transform with a MyTransform) and thus not worth the trouble of even trying. At least not just for a nicer syntax.

But is it? Or is there any other way this could be achieved?

Answer 1

Have you tried using Extension Methods? You can declare them like this:

public static class MyMonoExtensions {

    public static T GetOrAddComponent<T>(this Transform child) where T: Component {
        T result = child.GetComponent<T>();
        if (result == null) {
            result = child.gameObject.AddComponent<T>();
        }
        return result;
    }

}

You can call it like an instance method, then:

child.GetOrAddComponent<BoxCollider>();

See the link above for more details on extension methods.