byte[] Strbyte = Encoding.GetEncoding("big5").GetBytes(str);

            if (Strbyte.Length < len)

            {

                Strbyte = Encoding.GetEncoding("big5").GetBytes(str.PadRight(len, ' '));

            }

            Byte[] ThisByte = new Byte[len];

            if (Strbyte.Length > len)

            {

                Buffer.BlockCopy(Strbyte, 0, ThisByte, 0, len);

            }

            else

            {

                

                Buffer.BlockCopy(Strbyte, 0, ThisByte, 0, Strbyte.Length);

            }

            return Encoding.GetEncoding("big5").GetString(ThisByte);