private void FillAttendances() { List <Labdate> labDates = new List <Labdate>(); context.GetLabdatesOfLab(LabID) .ForEach(l => labDates.Add(dataAccess.ConvertLabdate(l))); Attendances = new ObservableCollection <LabDetailPresence>(); labDates.ForEach(lD => { context.GetPresentsOfLabdate(lD.LabdateID).ForEach(p => { var s = context.GetStudentOfPresent(p.presentID); Attendances.Add(new LabDetailPresence { // student StudentID = s.studentID, FirstName = s.firstName, LastName = s.lastName, MatricelNumber = s.matricelNumber, // presence PresentID = p.presentID, WasPresent = Convert.ToBoolean(p.wasPresent), Note = p.note, // labDate LabdateID = lD.LabdateID, Date = lD.Date }); }); }); RefreshCourseDetailView(); }