小编典典

如何使用Json.Net对具有附加属性的自定义集合进行序列化/反序列化

c#

我有一个自定义集合(实现IList),它具有一些自定义属性,如下所示:

class FooCollection : IList<Foo> {

    private List<Foo> _foos = new List<Foo>();
    public string Bar { get; set; }

    //Implement IList, ICollection and IEnumerable members...

}

序列化时,使用以下代码:

JsonSerializerSettings jss = new JsonSerializerSettings() {
    TypeNameHandling = TypeNameHandling.Auto
};
string serializedCollection = JsonConvert.SerializeObject( value , jss );

它正确地序列化和反序列化所有收集项;但是,FooCollection不会考虑该类中的任何其他属性。

无论如何,有没有将它们包括在序列化中?


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2020-05-19

共1个答案

小编典典

问题如下:当对象实现时IEnumerable,JSON.net将其标识为值数组,并按照数组Json语法(不包括属性)对其进行序列化,例如:

 [ {"FooProperty" : 123}, {"FooProperty" : 456}, {"FooProperty" : 789}]

如果要序列化它保留属性,则需要通过定义一个custom来手工处理该对象的序列化JsonConverter

// intermediate class that can be serialized by JSON.net
// and contains the same data as FooCollection
class FooCollectionSurrogate
{
    // the collection of foo elements
    public List<Foo> Collection { get; set; }
    // the properties of FooCollection to serialize
    public string Bar { get; set; }
}

public class FooCollectionConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(FooCollection);
    }

    public override object ReadJson(
        JsonReader reader, Type objectType, 
        object existingValue, JsonSerializer serializer)
    {
        // N.B. null handling is missing
        var surrogate = serializer.Deserialize<FooCollectionSurrogate>(reader);
        var fooElements = surrogate.Collection;
        var fooColl = new FooCollection { Bar = surrogate.Bar };
        foreach (var el in fooElements)
            fooColl.Add(el);
        return fooColl;
    }

    public override void WriteJson(JsonWriter writer, object value, 
                                   JsonSerializer serializer)
    {
        // N.B. null handling is missing
        var fooColl = (FooCollection)value;
        // create the surrogate and serialize it instead 
        // of the collection itself
        var surrogate = new FooCollectionSurrogate() 
        { 
            Collection = fooColl.ToList(), 
            Bar = fooColl.Bar 
        };
        serializer.Serialize(writer, surrogate);
    }
}

然后按以下方式使用它:

var ss = JsonConvert.SerializeObject(collection, new FooCollectionConverter());

var obj = JsonConvert.DeserializeObject<FooCollection>(ss, new FooCollectionConverter());
2020-05-19