private void RemoveStudFromLab(student s, lab l) { // delete old presents of student context.GetLabdatesOfLab(LabID).ForEach(ld => { context.GetPresentsOfLabdate(ld.labdateID) .Where(p => p.student_studentID == s.studentID) .ToList() .ForEach(p => { dataAccess.PresentContext.Remove(p.presentID); }); }); // delete old taskDones of student context.GetTasksOfLab(LabID).ForEach(t => { context.GetTaskDonesOfTask(t.taskID) .Where(tD => tD.student_studentID == s.studentID) .ToList() .ForEach(tD => { dataAccess.TaskDoneContext.Remove(tD.taskDoneID); }); }); context.RemoveStudFromLab(s, l); }