问VirtualButtonBehaviour语法中的编译错误

EN

using System.Collections;    
using System.Collections.Generic;    
using UnityEngine;    
using Vuforia;

public class XYZScript : MonoBehaviour,IVirtualButtonEventHandler { 
    public GameObject xgo, ygo;
// Start is called before the first frame update
    void Start()
    {
        VirtualButtonBehaviour[] vrb = GetComponentInChildren<VirtualButtonBehaviour>();
        for(int i=0; i<vrb.Length; i++)
        {
            vrb[i].RegisterEventHandler(this);
        }
        xgo.SetActive(false);
        ygo.SetActive(false);        
    }

VirtualButtonBehaviour[] vrb = GetComponentInChildren<VirtualButtonBehaviour>();