HarmonyOS CustomDialog中的CustomDialogController 为undefined

showMsgDialog(msg: string) { 
  let dialogController = new CustomDialogController({ 
    builder: TMsgDialog({ 
      msg: msg, 
      rightBtn: "我知道了", 
      rightCallback: () => { 
        dialogController.close(); 
      } 
    }), 
    customStyle: true, 
    autoCancel: false, 
    alignment: DialogAlignment.Center, 
    maskColor: 0x77000000 
  }); 
  dialogController.open(); 
}