SetActive And Get SizeDelta value

Unity Engine
,
1

Please understand that I am not good at English before the text.

I want to get RectTransform.sizeDelta.y which is inactive object.
So I Use This Code

void OnEnable()
    {
        this.transform.GetChild(1).gameObject.SetActive(true);
        Debug.Log(this.transform.GetChild(1).gameObject.GetComponent<RectTransform>().sizeDelta.y);
        this.transform.GetChild(1).gameObject.SetActive(false);
    }

But, It Returns 0…

How Can I fix It?

2

Well…
I used a different method.

this.transform.GetChild(1).gameObject.SetActive(true);
        Debug.Log(this.transform.GetChild(1).gameObject.GetComponent<Text>().preferredHeight);
        this.transform.GetChild(1).gameObject.SetActive(false);

this code returns meaningful values

Thanks