c# - 将 JSON 数据保存到 C# 自定义对象中

Question

过去几天我一直在研究这个问题，我希望有人能阐明问题所在。

我创建了这个自定义对象:

public class WorldInformation
{
    public string ID { get; set; }
    public string name { get; set; }
}

和这个 JSON 数据:

string world = "[{\"id\":\"1016\",\"name\":\"Sea of Sorrows\"}, {\"id\":\"1008\",\"name\":\"Jade Quarry\"},{\"id\":\"1017\",\"name\":\"Tarnished Coast\"},{\"id\":\"1006\",\"name\":\"Sorrow's Furnace\"},{\"id\":\"2014\",\"name\":\"Gunnar's Hold\"}]";

我可以通过反序列化将数据成功保存在我的自定义对象中:

List<WorldInformation> worlds = JsonConvert.DeserializeObject<List<WorldInformation>>(world);

但是……

当我像这样创建自定义对象时

public class EventItems
{
    public string World_ID { get; set; }
    public string Map_ID { get; set; }
    public string Event_ID { get; set; }
    public string State { get; set; }        
}

并且有像这样的 JSON 数据:

string eventItem = "{\"events\":[{\"world_id\":1011,\"map_id\":50,\"event_id\":\"BAD81BA0-60CF-4F3B-A341-57C426085D48\",\"state\":\"Active\"},{\"world_id\":1011,\"map_id\":50,\"event_id\":\"330BE72A-5254-4036-ACB6-7AEED05A521C\",\"state\":\"Active\"},{\"world_id\":1011,\"map_id\":21,\"event_id\":\"0AC71429-406B-4B16-9F2F-9342097A50AD\",\"state\":\"Preparation\"},{\"world_id\":1011,\"map_id\":21,\"event_id\":\"C20D9004-DF6A-4217-BF25-7D6B5788A94C\",\"state\":\"Success\"}]}";

反序列化时出错

 List<EventItems> events = JsonConvert.DeserializeObject<List<EventItems>>(eventItem);

我得到的错误信息是:

Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[WebApplication1.EventItems]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.

To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.

Path 'events', line 1, position 10.

Answer 1

不幸的是，没有办法像 XmlSerializer 那样指定根 Json 元素。

参见 How to deserialize JSON array with "root" element for each object in array using Json.NET?

public class EventItems
{
    public EventItems()
    {
        Events = new List<EventItem>();
    }

    public List<EventItem> Events { get; set; }
}

public class EventItem
{
    public string World_ID { get; set; }
    public string Map_ID { get; set; }
    public string Event_ID { get; set; }
    public string State { get; set; }        
}

用法:

string eventItem = "{\"events\":[{\"world_id\":1011,\"map_id\":50,\"event_id\":\"BAD81BA0-60CF-4F3B-A341-57C426085D48\",\"state\":\"Active\"},{\"world_id\":1011,\"map_id\":50,\"event_id\":\"330BE72A-5254-4036-ACB6-7AEED05A521C\",\"state\":\"Active\"},{\"world_id\":1011,\"map_id\":21,\"event_id\":\"0AC71429-406B-4B16-9F2F-9342097A50AD\",\"state\":\"Preparation\"},{\"world_id\":1011,\"map_id\":21,\"event_id\":\"C20D9004-DF6A-4217-BF25-7D6B5788A94C\",\"state\":\"Success\"}]}";

var items = JsonConvert.DeserializeObject<EventItems>(eventItem);