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, @"[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;
        }