LINQ to datatable 链接查询

            List<DoctorQueue> lst = new List<DoctorQueue>();
            try
            {
                DataSet ds = DBHelper.ExecuteDataSet("exec API_GetDoctorQueue '" + fhp_id + "','" + fDeptId + "'");

                DataTable dt1 = ds.Tables[0];
                DataTable dt2 = ds.Tables[1];

                lst = (from a in dt2.AsEnumerable()
                       join b in dt1.AsEnumerable()
                       on new { temp = a.Field<int>("fID") } equals new { temp = b.Field<int>("fDoctorID") }
                       into temp
                       from t in temp.DefaultIfEmpty()
                       select new DoctorQueue
                       {
                           fID = a.Field<int>("fID"),
                           fDoctorName = a.Field<string>("fDoctorName") == null ? "" : a.Field<string>("fDoctorName"),
                           fDeptName = a.Field<string>("fDeptName") == null ? "" : a.Field<string>("fDeptName"),
                           fTitle = a.Field<string>("fTitle") == null ? "" : a.Field<string>("fTitle"),
                           fSpecialty = a.Field<string>("fSpecialty") == null ? "" : a.Field<string>("fSpecialty"),
                           fQueueNum = a.Field<int>("fQueueNum"),
                           fAverageWaitingTime = a.Field<int>("fAverageWaitingTime"),
                           fIsOnLine = t.Field<bool>("fIsOnLine"),//Convert.ToBoolean(t["fIsOnLine"])也可
                           fImgUrl = a.Field<string>("fImgUrl") == null ? "" : a.Field<string>("fImgUrl")
                       }).ToList<DoctorQueue>();
            }
            catch { }
            return lst;

　　a为主表