将派生类作为基类泛型类返回

Question

I'm writing unity scripts on C#. I've got my base class:

BaseMonoBehavior<T> : MonoBehaviour where T : BasePresenter

Some scripts extend this class, fe:

MyMonoBehaviour : BaseMonoBehaviour<MyPresenter> 
// MyPresenter extends BasePresenter

Then I have a type class with method, which adds this scripts as components to GameObject according to it's value:

void addComponentTo(GameObject gameObject) {
    if (myType == TYPE_A) {
        var script = gameObject.AddComponent<MyMonoBehaviour>();
    }
}

It's okay, but what can I do, if I want to return created script as base class? I want but can't write something like this:

BaseMonoBehaviour addComponentTo(GameObject gameObject) {
    if (myType == TYPE_A) {
        var script = gameObject.AddComponent<MyMonoBehaviour>();
        return script;
    }
    return null;
}

So, my question is simple - how can I do this? I want to use some methods of base class in the method, which calls addComponentTo ...

PS Afterwards I'd like to get MyMonoBehaviour as BaseMonoBehaviour from GameObject , if it's possible, but it's yet another question.

Answer 1

Since BaseMonoBehaviour is generic on a presenter class, you could make AddComponentTo generic as well:

BaseMonoBehaviour<TP> AddComponentTo(GameObject gameObject) where TP : BasePresenter {
    if (myType == TYPE_A) {
        var script gameObject.AddComponent<MyMonoBehaviour>();
        return script;
    }
    return null;
}

Then the caller would be able to call it as follows:

var component = AddComponentTo<MyPresenter>(gObj);

This requires all generic instances returned by AddComponentTo to be generic on the same type that you can specify at invocation point.

Note: If AddComponentTo creates generic instances that are generic on the same presenter, you could even make it non-generic, like this:

BaseMonoBehaviour<MyPresenter> AddComponentTo(GameObject gameObject) {
    if (myType == TYPE_A) {
        var script gameObject.AddComponent<MyMonoBehaviour>();
        return script;
    }
    return null;
}

and call it like this:

var component = AddComponentTo(gObj);