public Course TryAddCourse(CourseContract courseContract, out string message) { if (!Utilities.IsValidCourseContract(courseContract, out message)) { return(null); } try { if (_coursesRepository.GetCourseByName(courseContract.Name) != null) { message = "Course with the same name is already exist"; return(null); } var course = new Course(courseContract); return(_coursesRepository.AddCourse(course)); } catch (DALException e) { // LOG throw new BLException("There was a problem adding new student", e); } }