C# BASE64

static class MyBase64
    {
        public static Encoding[] encoding = {
                                    Encoding.ASCII,
                                    Encoding.Unicode,
                                    Encoding.UTF7,
                                    Encoding.UTF8,
                                    Encoding.UTF32,
                                    Encoding.BigEndianUnicode,
                                    Encoding.GetEncoding("GB2312"),
                                    Encoding.GetEncoding("GBK")
                                   };
        static public string EncodeBase64(string Base64_Message, int index)
        {
            try
            {
                return System.Convert.ToBase64String(encoding[index].GetBytes(Base64_Message));
            }
            catch { MessageBox.Show("加密失败"); return ""; }
        }


        public static string DecodeBase64(string Base64_Ciphertext, int index)
        {
            try
            {
                return encoding[index].GetString(System.Convert.FromBase64String(Base64_Ciphertext));
            }
            catch
            {
                MessageBox.Show("该密文不适用于该种编码");
                return "";
            }
        }
    }