问在Start()中设置后不更改Unity3D文本

EN

public class ChangeText : MonoBehaviour

    {
        public GameObject CanvasPrefab; 
        private GameObject runtimeCanvas;
        public string runtimeText = "something";
        private Text textRef;
        // Start is called before the first frame update
        void Start()
        {
            runtimeCanvas = GameObject.Instantiate(CanvasPrefab);
            textRef = runtimeCanvas.GetComponentInChildren<Text>();
        }

        // Update is called once per frame
        void Update()
        {
            textRef.text = runtimeText;
        }
    }