c# newtonsoft解析内部数组

我反序列化我的json到一个模型类很好，但我想在保存到sqlite之前做一些关于盒子数组的工作，我被困在循环通过所有的盒子，并获得值。

{
"data": [ // single outer array
    {
        "id": 8620379, 
        "business_id": 191, 
        "business_name": "yada", 
        "boxes": [
            {
                "box_id": 485, 
                "box_name": "5/6", 
                "box_group": null
            }, 
            {
                "box_id": 483, 
                "box_name": "1/2", 
                "box_group": null
            }, 
            {
                "box_id": 484, 
                "box_name": "3/4", 
                "box_group": null
            }
        ]
    }, 
    {
        "id": 8636759, 
        "business_id": 257, 
        "business_name": "something else", 
        "boxes": [
            {
                "box_id": 1176, 
                "box_name": "FC", 
                "box_group": null
            }
        ]
    }, // and more boxes

public class Box
{
    public int box_id { get; set; }
    public string box_name { get; set; }
    public object box_group { get; set; }
}
public class Datum
{
    public int id { get; set; }
    public int business_id { get; set; }
    public string business_name { get; set; }
    public List<Box> boxes { get; set; }
}
public class RootObject
{
    public List<Datum> data { get; set; }
}

RootObject obj = JsonConvert.DeserializeObject<RootObject>("your json string");