String直接換成Bytes

string 長怎樣，轉過去bytes就怎樣
限制string長度必須為偶數

    protected byte[] StringToBytes(string HexString)
    {
        int byteLength = HexString.Length / 2;
        byte[] bytes = new byte[byteLength];
        string hex;
        int j = 0;
        for (int i = 0; i < bytes.Length; i++)
        {
            hex = new String(new Char[] { HexString[j], HexString[j + 1] });
            bytes[i] = HexToByte(hex);
            j = j + 2;
        }
        return bytes;
    }

    private byte HexToByte(string hex)
    {
        if (hex.Length > 2 || hex.Length <= 0)
            throw new ArgumentException("hex must be 1 or 2 characters in length");
        byte newByte = byte.Parse(hex, System.Globalization.NumberStyles.HexNumber);
        return newByte;
    }