public void InsertAttendance() { try { using (KungFuEntities2 entities = new KungFuEntities2()) { var studentID = (from obj in entities.tblStudents where obj.STU_NUM == txtStudentNumber.Text select obj.STU_ID).FirstOrDefault(); var classID = int.Parse(ddlClassType.SelectedValue); //DateTime dtFrom = Convert.ToDateTime(txtDate.Text); //var AttendanceID = (from obj in entities.tblAttendences // where obj.CLASS_ID == ddlClassType.SelectedIndex && obj.STU_ID == studentID && obj.ATT_DATE == dtFrom // select obj.ATT_ID).FirstOrDefault(); int ihdnPKID = int.Parse(hdnPKId.Value); Int32 AttendanceID = 0; if (ihdnPKID == 0) { AttendanceID = (from obj in entities.tblAttendences where obj.CLASS_ID == classID && obj.STU_ID == studentID select obj.ATT_ID).FirstOrDefault(); } else { AttendanceID = (from obj in entities.tblAttendences where obj.CLASS_ID == classID && obj.STU_ID == studentID && obj.ATT_ID != ihdnPKID select obj.ATT_ID).FirstOrDefault(); } if (studentID != 0 && AttendanceID == 0) { var objAttendence = entities.tblAttendences.Where(s => s.ATT_ID == ihdnPKID).OrderByDescending(s => s.ATT_ID).FirstOrDefault(); if (objAttendence == null) { objAttendence = new tblAttendence(); } objAttendence.STU_ID = Convert.ToInt32(studentID); objAttendence.ATT_DATE = DateTime.ParseExact(txtDate.Text, "MM/dd/yyyy", null); objAttendence.CLASS_ID = Convert.ToInt32(ddlClassType.SelectedValue); objAttendence.ATT_CREATED_BY = entities.tblInstructors.AsEnumerable().FirstOrDefault().INSTRUCTOR_ID; objAttendence.ATT_CREATED_DATE = DateTime.Now; objAttendence.STU_ID = Convert.ToInt32(studentID); objAttendence.ATT_STATUS = chkIsPresent.Checked; if (objAttendence.ATT_ID == 0) { entities.tblAttendences.Add(objAttendence); } else { objAttendence.ATT_MODIFY_BY = entities.tblInstructors.Select(x => x.INSTRUCTOR_ID).FirstOrDefault(); objAttendence.ATT_MODIFIED_DATE = DateTime.Now; entities.Entry(objAttendence).State = System.Data.Entity.EntityState.Modified; } entities.SaveChanges(); objAttendence = null; if (hdnPKId.Value != "0") { Response.Redirect("AttendanceList.aspx"); } ResetControls(); divMessage.Visible = true; divErrorMsg.Visible = false; } else { if (studentID == 0) { divErrorMsg.InnerHtml = ""; divErrorMsg.InnerText = "Student does not exist with this number."; } else { divErrorMsg.InnerHtml = ""; divErrorMsg.InnerText = "Attendance for this student with class time and date already exist."; } divErrorMsg.Visible = true; divMessage.Visible = false; return; } } } catch (Exception ex) { } }