public static class Base64
    {
        public  static byte[] DecodeToBytes(string strText)
        {
            try
            {
                return Convert.FromBase64String(strText);
            }
            catch (Exception e)
            {
                Utility.LogError("decodeToBytes:" + e.Message);
                
                return Encoding.Default.GetBytes("\0");
            }
        }

/// <summary>
        /// Decoded a Base64 encoded string using the Default encoding of the system
        /// </summary>
        /// <param name="base64Encoded">Source string to decode</param>
        /// <returns>A decoded string</returns>
        public static string Decode(string base64Encoded)
        {
            //有可能因为二进制问题不能正确解码 dth,2010.12.15
            //return Encoding.Default.GetString(DecodeToBytes(base64Encoded));
            //ISO8859-1 字符串，8位，只有这种可以完整保留二进制
            Encoding _encoding = Encoding.GetEncoding(28591);
            return _encoding.GetString(DecodeToBytes(base64Encoded));
        }

/// <summary>
        /// Decoded a Base64 encoded string using a specified encoding
        /// </summary>
        /// <param name="base64Encoded">Source string to decode</param>
        /// <param name="nameOfEncoding">The name of the encoding to use</param>
        /// <returns>A decoded string</returns>
        public static string Decode(string base64Encoded, string nameOfEncoding)
        {
            try
            {
                return Encoding.GetEncoding(nameOfEncoding).GetString(DecodeToBytes(base64Encoded));
            }
            catch(Exception e)
            {
                Utility.LogError("decode: " + e.Message);
                return Decode(base64Encoded);
            }
        }
    }