C# JSON字符串首字母转大写

/// <summary>        /// Json字符串首字母转大写        /// </summary>        /// <param name="strJsonData">json字符串</param>        /// <returns></returns>        public static string UpperFirst(string strJsonData)        {            MatchCollection matchCollection = Regex.Matches(strJsonData, "\\\"[a-zA-Z0-9]+\\\"\\s*:");            foreach (Match item in matchCollection)            {                string res = Regex.Replace(item.Value, @"\b[a-z]\w+", delegate (Match match)                {                    string val = match.ToString();                    return char.ToUpper(val[0]) + val.Substring(1);                });                strJsonData = strJsonData.Replace(item.Value, res);            }            return strJsonData;        }