public static Student GetStudentDataByUser(User user) { long facultyNumber; if (!long.TryParse(user.FacultyNumber, out facultyNumber)) { //error invalid faculty number return(null); } Student student = null; foreach (User u in UserData.TestUsers) { long tempFacultyNumber = -1; if (long.TryParse(u.FacultyNumber, out tempFacultyNumber) && facultyNumber == tempFacultyNumber) { student = StudentData.getStudentByFacutlyNumber(facultyNumber); break; } } //error student not found return(student); }