Linq--一个集合中查找另一个集合，需熟悉这种写法

//获取科室与病区授权的护士信息
        public List<SYS_ZGKSBQDYK> GetUserWardMapByWardCode(string wardCode)
        {
            List<SYS_ZGKSBQDYK> userWardMaps = DataHelper.DataObj.QueryTable<SYS_ZGKSBQDYK>(SystemType.H0, o => o.KSDM == wardCode && o.LB == 1).ToList();
            List<SYS_BQDMK> BqdmkList = QueryBqxx();
            return userWardMaps.FindAll(k => BqdmkList.Select(b => b.ID).Contains(k.KSDM));
        }