C# 在知道对象时编译json 而不调用json类

StringBuilder sb = new StringBuilder();
            sb.Append('[');
           
            foreach (var ss in list)
            {
                sb.Append("{\"type\":\""+ss.type+"\",\"name\":\""+ss.name+"\",\"size\":\""+ss.size+"\",\"createTime\":\""+ss.createTime+"\",\"updateTime\":\""+ss.updateTime+"\"},");                
            }
            sb[sb.Length - 1] = ']';
            string json = sb.ToString();
            return json;