//Deserialize<T>(String) 将JSON字符串转化为类型T。
JavaScriptSerializer jss = new JavaScriptSerializer();
IList<IDictionary<string, string>> remarkContent = jss.Deserialize<IList<IDictionary<string, string>>>("字符串");
remarkContent = remarkContent == null ? new List<IDictionary<string, string>>() : remarkContent;
IDictionary<string, string> _contentlist = new Dictionary<string, string>();
//向集合添加新的数据
_contentlist["Remark"] = Remark;
_contentlist["CreateDate"] = timenow.ToString();
_contentlist["CreateBy"] = username;
remarkContent.Add(_contentlist);
//转为字符串
remarkList = jss.Serialize(remarkContent);
原文：https://www.cnblogs.com/sky2blue/p/10521668.html