如何使用Json.Net反序列化枚举数组？

Question

我有一个像这样的JSON:

[{ 
    "agencyId": "myCity",
    "road": {
    "note": "",
        "lat": "45.321",
        "lon": "12.21",
        "streetCode": "290",
        "street": "street1",
        "fromNumber": "",
        "toNumber": "",
        "fromIntersection": "",
        "toIntersection": ""
    },
    "changeTypes": ["PARKING_BLOCK", "ROAD_BLOCK"],
},]

和这样的一个类:

public class AlertRoad : BaseAlert
{
    [JsonProperty("agencyId")]
    [JsonConverter(typeof(StringEnumConverter))]
    public AgencyType AgencyId { get; set; }

    [JsonProperty("changeTypes")]
    [JsonConverter(typeof(StringEnumConverter))]
    public ChangeType[] ChangeTypes { get; set; }

    [JsonProperty("road")]
    public Road RoadInfo { get; set; }
}

AgencyType是枚举,AgencyId的反序列化和序列化工作.

ChangeType是另一个枚举,但ChangeTypes的反序列化和序列化不起作用.我假设原因是ChangeTypes是一个枚举值数组.

问题是:如何反序列化/序列化ChangeTypes字段,或者通常是枚举值数组？

我尝试定义自己的字段转换器,名为ChangeTypeConverter,并将StrinEnumConverter更改为ChangeTypeConverter for ChangeTypes字段,但在ReadJson函数中,reader的值为null.

public class ChangeTypeConverter : JsonConverter
{
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {

    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        var val = reader.Value;
        //val is null?!?
        return val;
    }

    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(ChangeType);
    }
}

Answer 1

在StringEnumConverter预期只有一个枚举值.因为ChangeTypes是一个数组,所以需要以不同的方式注释属性以使其工作.

试试这个:

[JsonProperty("changeTypes", ItemConverterType=typeof(StringEnumConverter))]
public ChangeType[] ChangeTypes { get; set; }

Answer 2

无需编写自定义JsonConverter即可对Enum数组进行序列化/反序列化。与其装饰父模型中的单个属性，不如使用StringEnumConverter JsonConverter属性装饰Enum。

例如：

以下环境模型具有Shelter枚举属性和枚举Shelter数组[]

public class Environment
{

    public string Name { get; set; }
    public Shelter Shelter { get; set; }
    public Shelter[] Shelters { get; set; }
}

[JsonConverter(typeof(StringEnumConverter))]
public enum Shelter
{
    Indoor,
    Outdoor
}

输出json：-

 {
   "name": "",
   "shelter": "Indoor",
    "shelters": [
       "Indoor",
       "Outdoor"
  ]
 }