public static class ExtentMethod
{
    public static string ToUnicodeString(this string str)
    {
        StringBuilder strResult = new StringBuilder();
        if (!string.IsNullOrEmpty(str))
        {
            for (int i = 0; i < str.Length; i++)
            {
                strResult.Append("\\u");
                strResult.Append(((int)str[i]).ToString("x"));
            }
        }
        return strResult.ToString();
    }

    public static string FromUnicodeString(this string str)
    {
        //最直接的方法Regex.Unescape(str);
        StringBuilder strResult = new StringBuilder();
        if (!string.IsNullOrEmpty(str))
        {
            string[] strlist = str.Replace("\\", "").Split('u');
            try
            {
                for (int i = 1; i < strlist.Length; i++)
                {
                    int charCode = Convert.ToInt32(strlist[i], 16);
                    strResult.Append((char)charCode);
                }
            }
            catch (FormatException ex)
            {
                return Regex.Unescape(str);
            }
        }
        return strResult.ToString();
    }
}