private IQueryable <Student> getStudentList(string searchString)
        {
            System.Linq.IQueryable <Student> students;
            if (System.String.IsNullOrEmpty(searchString))
            {
                students = studentCRUD.StudentList();
            }
            else
            {
                students = studentCRUD.SearchStudentList(searchString);
            }

            return(students);
        }