static void Main(string[] args) { var Spottingname = "112"; var plateno = "222"; var processid = "c8b79051249940acbeca5dd951d2c168"; DataBaseConnect(); List<PUNISH_ILLEGALVEHICLE_REALModel> pulist = new List<PUNISH_ILLEGALVEHICLE_REALModel>(); using (IRepository<PUNISH_ILLEGALVEHICLE_REALModel> repository = RepositoryManager.CreateRepository<PUNISH_ILLEGALVEHICLE_REALModel>()) { var list = repository.GetModels().ToList(); //DataTable dt = ListToDt<PUNISH_ILLEGALVEHICLE_REALModel>(list); var q = from u in list select u; if (!string.IsNullOrEmpty(Spottingname)) { q = q.Where(p => p.Spottingname == Spottingname); } if (!string.IsNullOrEmpty(plateno)) { q = q.Where(p => p.plateno == plateno); } if (!string.IsNullOrEmpty(processid)) { q = q.Where(p => p.processid == processid); } list = q.ToList(); //上边的所有if,只有到此处才会执行 } }