public string HanZi(string str)
        {

            string temp = "";

            if (!string.IsNullOrEmpty(str))
            {
                foreach (char c in str)
                {
                    if (char.GetUnicodeCategory(c) == UnicodeCategory.OtherLetter)
                    {
                        temp += c;
                    }
                }
            }

            return temp;
        }