abp中linq的应用

 private IQueryable<MembershipEntity> SelectOrScrrenMember(GetMemberInput input)
        {
            string[] userDefinedFilter = null;

            if (!input.UserDefinedFilter.IsNullOrWhiteSpace())
            {
                userDefinedFilter = input.UserDefinedFilter.Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);//不保留空元素
            }

            var query = from m in _memberRepository.GetAll()
                        join s in _VipcardRepository.GetAll() on m.Id equals s.MEMBER_CODE
                        join g in _VipcardgradeRepository.GetAll() on s.VIP_CARD_GRADE equals g.CARDGRADECODE
                        select new MembershipEntity
                        {
                            Id = m.Id,
                            ENGLISH_NAME = m.ENGLISH_NAME,
                            CHINESE_NAME = m.CHINESE_NAME,
                            E_MAIL = m.E_MAIL,
                            PHONE_NO_MOBILE = m.PHONE_NO_MOBILE,
                            PHONE_NO_HOME = m.PHONE_NO_HOME,
                            PHONE_NO_OFFICE = m.PHONE_NO_OFFICE,
                            ID_NO = m.ID_NO,
                            REMARK = m.REMARK,
                            CARD_NO = s.CARD_NO,
                            VIP_CARD_GROUP = s.VIP_CARD_GROUP,
                            VIP_CARD_GRADE = s.VIP_CARD_GRADE,
                            CARDGRADEDESC = g.CARDGRADEDESC,
                            IS_ARTIST = m.IS_ARTIST,
                            STATUS = m.STATUS,
                            UserDefinedField = m.USER_DEFINED_FIELD
                        };
            query = query.WhereIf(!input.ENGLISH_NAME.IsNullOrWhiteSpace(), item => item.ENGLISH_NAME.Contains(input.ENGLISH_NAME))
                .WhereIf(!input.MEMBER_CODE.IsNullOrWhiteSpace(), item => item.Id.Contains(input.MEMBER_CODE))
                .WhereIf(!input.PHONE_NO_HOME.IsNullOrWhiteSpace(), item => item.PHONE_NO_HOME.Contains(input.PHONE_NO_HOME))
                .WhereIf(!input.PHONE_NO_MOBILE.IsNullOrWhiteSpace(), item => item.PHONE_NO_MOBILE.Contains(input.PHONE_NO_MOBILE));

            if (userDefinedFilter != null)
            {
                foreach (var filter in userDefinedFilter)
                {
                    query = query.Where(item => item.UserDefinedField.Contains(filter));
                }
            }

            return query;

        }