c# datatable 转json

public static string DataTableToJson(DataTable dt)
        {
            List<object> list = new List<object>();
            foreach(DataRow dr in dt.Rows)
            {
                Dictionary<string, object> dic = new Dictionary<string, object>();
                foreach(DataColumn col in dt.Columns)
                {
                    dic.Add(col.ColumnName, dr[col.ColumnName]);
                }

                dynamic obj = new ExpandoObject();
                foreach(KeyValuePair<string,object> item in dic)
                {
                    ((IDictionary<string, object>)obj).Add(item.Key, item.Value);
                }
                list.Add(obj);
            }
            string json = new JavaScriptSerializer().Serialize(list);
            return

重点：dynamic obj = new ExpandoObject();
匿名类的动态添加对象