public Encoding dos = Encoding.GetEncoding(866);
        public Encoding win = Encoding.GetEncoding(1251);
        public Encoding ascii = Encoding.ASCII;
        public string DosToWin(string s)
        {
            return win.GetString(dos.GetBytes(s));
        }
        public string WinToDos(string s)
        {
            return dos.GetString(win.GetBytes(s));
        }

        public static string ConvertEncoding(string value, Encoding src, Encoding trg)
        {
            Decoder dec = src.GetDecoder();
            byte[] ba = trg.GetBytes(value);
            int len = dec.GetCharCount(ba, 0, ba.Length);
            char[] ca = new char[len];
            dec.GetChars(ba, 0, ba.Length, ca, 0);
            return new string(ca);
        }

            using (FileStream fs = new FileStream(FileName, FileMode.Create, FileAccess.Write))
            {
                using (StreamWriter sw = new StreamWriter(fs, Encoding.Default)) //Encoding.XXX
                {
                    sw.WriteLine(_data);
                }
            }