public static Boolean Kiem_tra(String Chuoi) { Boolean kq = true; try { String[] M = Chuoi.Split(new char[] { Ky_tu_phan_cach }); for (int i = 0; i < M.Length; i++) { if (!XL_PHAN_SO.Kiem_tra(M[i])) { kq = false; break; } } } catch (Exception Loi) { kq = false; } return(kq); }