根据给定的列名动态生成json数组

List<string> cols = new List<string>() { "姓名","性别","年龄"};

1.使用JArray,JObject对象

//JObject
            JArray arr = new JArray();
            JObject obj = new JObject();
            foreach (var col in cols)
            {
                obj[col] = col + "_test";
            }
            arr.Add(obj);

            //获得对象的所有字段名
            var itemProperties = ((JObject)arr[0]).Properties().ToList();
            foreach (var item in itemProperties)
            {
                var v = item.Name+":"+item.Value;
            }

            string json1 = JsonEncode(arr);

2.使用Datatable

//Datatable
            DataTable dt = new DataTable();
            var row = dt.NewRow();
            foreach (var col in cols)
            {
                dt.Columns.Add(col);
                row[col] = col + "_test";
            }
            dt.Rows.Add(row);
            string json2 = JsonEncode(dt);

            //var colName=dt.Columns[0].ColumnName;

3.使用Dynamic对象

//Dynamic http://www.cnblogs.com/xuejianxiyang/p/4964739.html
            dynamic dobj = new System.Dynamic.ExpandoObject();

            var dic = (IDictionary<string, object>)dobj;
            foreach (var col in cols)
            {
                dic[col] = col + "_test";
            }

            foreach (var fieldItem in (IDictionary<String, Object>)dobj)
            {//获得对象的所有字段名
                var v = (fieldItem.Key + ": " + fieldItem.Value);
            }

            List<System.Dynamic.ExpandoObject> list = new List<System.Dynamic.ExpandoObject>();
            list.Add(dobj);

            string json3 = JsonEncode(list);

public static string JsonEncode<T>(T jsonstruct, bool withIndentFormat = true)
{
//var setting=new JsonSerializerSettings();
//setting.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;

Formatting format = Formatting.Indented;
if (!withIndentFormat)
{
format = Formatting.None;
}

return JsonConvert.SerializeObject(jsonstruct, format,
new JsonSerializerSettings()
{
ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
PreserveReferencesHandling = PreserveReferencesHandling.None
});

}

From:http://www.cnblogs.com/xuejianxiyang/p/6639610.html