public IEnumerable <CdmaBtsView> QueryCollegeBtss(string collegeName) { var ids = _repository.GetBtsIds(collegeName); var btss = ids.Select(_btsRepository.Get).Where(bts => bts != null).ToList(); return(Mapper.Map <List <CdmaBts>, IEnumerable <CdmaBtsView> >(btss)); }