class HexTest
{
    static char[] hexDigits = {
        '0', '1', '2', '3', '4', '5', '6', '7',
        '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

    public static string ToHexString(byte[] bytes) {
        char[] chars = new char[bytes.Length * 2];
        for (int i = 0; i < bytes.Length; i++) {
            int b = bytes[i];
            chars[i * 2] = hexDigits[b >> 4];
            chars[i * 2 + 1] = hexDigits[b & 0xF];
        }
        return new string(chars);
    }

    static void Main() {
        byte[] b = {0x00, 0x12, 0x34, 0x56, 0xAA, 0x55, 0xFF};
        Console.WriteLine(ToHexString(b));
        Console.WriteLine(BitConverter.ToString(b));//Fireworks自带方法    
   }
}
//运行结果
//00123456AA55FF
//00-12-34-56-AA-55-FF