JSON.NET与自定义集合（含集合属性） [英] JSON.NET with custom collection (with collection properties)

问题描述

我有一个自定义集合（实现IList），其中有一些自定义属性如下

I have a custom collection (implements IList) which has some custom properties as following

class FooCollection : IList<Foo>{

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

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

}

当我序列化，我用下面的code

When I serialize, I use the following code

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

它的工作原理，它系列化所有的收集，妥善反序列化的藏品，但是任何额外的属性给 FooCollection 类都没有考虑到。

反正是有，包括他们的序列化？

Is there anyway to include them in the serialization?

推荐答案

这个问题是这样的：当一个对象实现的IEnumerable ，JSON.net其识别为一个数组值和序列化它下面的数组 JSON的语法（不包括物业）， 例如

The problem is the following: when an object implements IEnumerable, JSON.net identifies it as an array of values and serializes it following the array Json syntax (that does not include properties), e.g. :

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

如果你想保留的属性序列化它，你需要通过定义一个自定义的 JsonConverter 来处理由手对象的序列化：

If you want to serialize it keeping the properties, you need to handle the serialization of that object by hand by defining a custom 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);
    }
}

然后使用它，如下所示：

Then use it as follows:

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

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

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