C# Unicode编码

/// <summary>
        /// 汉字转换为Unicode编码
        /// </summary>
        /// <param name="str">要编码的汉字字符串</param>
        /// <returns>Unicode编码的的字符串</returns>
        public static string ToUnicode(string str)
        {
            byte[] bts = Encoding.Unicode.GetBytes(str);
            string r = "";
            for (int i = 0; i < bts.Length; i += 2) r += "\u" + bts[i + 1].ToString("x").PadLeft(2, '0') + bts[i].ToString("x").PadLeft(2, '0');
            return r;
        }
        /// <summary>
        /// 将Unicode编码转换为汉字字符串
        /// </summary>
        /// <param name="str">Unicode编码字符串</param>
        /// <returns>汉字字符串</returns>
        public static string ToGB2312(string str)
        {
            string r = "";
            MatchCollection mc = Regex.Matches(str, @"\u([w]{2})([w]{2})", RegexOptions.Compiled | RegexOptions.IgnoreCase);
            byte[] bts = new byte[2];
            foreach (Match m in mc)
            {
                bts[0] = (byte)int.Parse(m.Groups[2].Value, NumberStyles.HexNumber);
                bts[1] = (byte)int.Parse(m.Groups[1].Value, NumberStyles.HexNumber);
                r += Encoding.Unicode.GetString(bts);
            }
            return r;
        }