C# Unicode 中文转换

using System.Text.RegularExpressions;           

            string strJson = JsonConvert.SerializeObject(group);
            string outStr = "";

            Regex rx = new Regex("^[\u4e00-\u9fa5]$");
            if (!string.IsNullOrEmpty(strJson))
            {
                for (int i = 0; i < strJson.Length; i++)
                {
                    //将中文字符转为10进制整数，然后转为16进制unicode字符
                    if (rx.IsMatch(strJson[i].ToString()))
                    {
                        outStr += @"\u" + ((int)strJson[i]).ToString("x");
                    }
                    else
                    {
                        outStr += strJson[i].ToString();
                    }
                }
            }

            string strAA = Regex.Unescape(outStr);