สอบถามเรื่อง Error A referential integrity constraint violation occurred: The property value(s)

foreach (var i in position)
                {
                    m.id_actual = Int32.Parse(Request.Form["id_actual[" + i.Trim() + "]"]);
                    m.id_employee = employee;
                    m.id_oper_unit = Request.Form["oper_unit"];
                    m.id_department = Request.Form["department"];
                    m.id_position = i;
                    m.io = Request.Form["io"];
                    m.year = App_Setting.Config.nextYear;
                    m.head_count = Int32.Parse(Request.Form["head_count[" + i.Trim() + "]"]);
                    m.month1 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][1]"]);
                    m.month2 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][1]"]);
                    m.month3 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][1]"]);
                    m.month4 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][2]"]);
                    m.month5 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][2]"]);
                    m.month6 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][2]"]);
                    m.month7 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][3]"]);
                    m.month8 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][3]"]);
                    m.month9 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][3]"]);
                    m.month10 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][4]"]);
                    m.month11 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][4]"]);
                    m.month12 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][4]"]);
                    m.status = 1;
                    m.created_id = 1;
                    m.created_date = DateTime.Now;
                    m.updated_id = 1;
                    m.updated_date = DateTime.Now;
                    db.manpower_temp.Add(m);
                    db.SaveChanges();

                    //Insert Manpower_temp_log
                    mpLog.id_mp_temp = m.id_mp_temp; //รับค่า id จากตาราง manpower_temp มาเลย Error
                    mpLog.id_actual = Int32.Parse(Request.Form["id_actual[" + i.Trim() + "]"]);
                    mpLog.id_employee = employee;
                    mpLog.id_oper_unit = Request.Form["oper_unit"];
                    mpLog.id_department = Request.Form["department"];
                    mpLog.id_position = i;
                    mpLog.io = Request.Form["io"];
                    mpLog.year = App_Setting.Config.nextYear;
                    mpLog.head_count = Int32.Parse(Request.Form["head_count[" + i.Trim() + "]"]);
                    mpLog.month1 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][1]"]);
                    mpLog.month2 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][1]"]);
                    mpLog.month3 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][1]"]);
                    mpLog.month4 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][2]"]);
                    mpLog.month5 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][2]"]);
                    mpLog.month6 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][2]"]);
                    mpLog.month7 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][3]"]);
                    mpLog.month8 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][3]"]);
                    mpLog.month9 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][3]"]);
                    mpLog.month10 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][4]"]);
                    mpLog.month11 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][4]"]);
                    mpLog.month12 = Int32.Parse(Request.Form["quarter[" + i.Trim() + "][4]"]);
                    mpLog.status = 1;
                    mpLog.created_id = 1;
                    mpLog.created_date = DateTime.Now;
                    mpLog.updated_id = 1;
                    mpLog.updated_date = DateTime.Now;
                    db.manpower_temp_log.Add(mpLog);
                    db.SaveChanges();
                }