public void RemoveRange(IEnumerable <Major> majors) { if (majors.Count() == 0) { throw new ArgumentNullException("majors"); } var hasStudents = majors.Count(g => g.Students.Count > 0); if (hasStudents > 0) { throw new ForeignKeyEntityException("This major could not be removed. It has one or more students associated with it."); } _majorRepository.RemoveRange(majors); }