private void SetList() { string sdate = "", edate = ""; SelectedDate.GetStartEndDate(ref sdate, ref edate); var atnds = AttendanceRepo.GetStudentAttendance(SelectedStudenID, SelectedClassID, sdate, edate); int count = SelectedDate.GetDaysInMonth(); IEnumerable <StudentAttendance> _list = null; for (int i = 1; i <= count; i++) { bool isExisted = false; StudentAttendance temp = null; foreach (var item in atnds) { if (i == item.DayNumber) { item.isExisted = true; temp = item; isExisted = true; break; } } if (!isExisted) { temp = new StudentAttendance() { isPresent = false, DayNumber = i, DayName = sdate.AddDaysInDate(i).GetDayName() }; } _list = _list.Add(temp); } StudentAttendanceList = _list; }