我想用从本地数据库获取的数据填充我的DropdownSearch。请帮助我。

Future<dynamic> getList() async {
  final db = await getDatabase();
  final res = await db.rawQuery("SELECT * FROM tb_point_of_Sale");

  List<dynamic> list = 
      res.isNotEmpty ? res.map((c) => PointOfSale.fromJson(c)).toList() : [];
  }

body: Column(
  children: [
    DropdownSearch<String>(
      mode: Mode.MENU,
      items: PointOfSaleDao.db.getList(),
      showSearchBox: true,
      label: "Menu mode",
      hint: "point of sale in menu mode",
      onChanged: (value) {}
    ),
  ],
),