反序列化列表<AbstractClass>使用 newtonsoft.json

问题描述

我正在尝试序列化和反序列化 abstract 类列表(mustinherit for vb)，显然其中只有派生类的实例.

i'm trying to serialize and deserialize a list of abstract classes (mustinherit for vb), obviusly inside it there are only instances of derived classes.

我用 JsonProperty(ItemTypeNameHandling = TypeNameHandling.Auto) 修饰了列表参数，获得如下所示的输出:

I've decorated the list parameter with the JsonProperty(ItemTypeNameHandling = TypeNameHandling.Auto) obtaining an output that look like this:

但是当我反序列化它时一直说他不能反序列化抽象类.

But when i deserialize it keep saying that he cannot deserialize an abstract class.

http://james.newtonking.com/json/help/index.html?topic=html/SerializeTypeNameHandling.htm

public class ConcreteClass
{
    private ObservableCollection<AbstractClass> _Nodes = new ObservableCollection<AbstractClass>();
    //<Newtonsoft.Json.JsonProperty(itemtypenamehandling:=Newtonsoft.Json.TypeNameHandling.Auto)>
    public ObservableCollection<AbstractClass> Nodes {
        get { return this._Nodes; }
    }
    public string Name { get; set; }
    public int Id { get; set; }
}

public abstract class AbstractClass
{
    private ObservableCollection<AbstractClass> _Nodes = new ObservableCollection<AbstractClass>();
    [Newtonsoft.Json.JsonProperty(itemtypenamehandling = Newtonsoft.Json.TypeNameHandling.Auto)]
    public ObservableCollection<AbstractClass> Nodes {
        get { return this._Nodes; }
    }
}

删除它的注释行！

推荐答案

确保在反序列化时指定 TypeNameHandling，按照文档:

Make sure you specify TypeNameHandling when deserializing, as per the docs:

// for security TypeNameHandling is required when deserializing
Stockholder newStockholder = JsonConvert.DeserializeObject<Stockholder>(jsonTypeNameAuto, new JsonSerializerSettings
{
    TypeNameHandling = TypeNameHandling.Auto
});

值得注意的是，文档正在反序列化一个包含抽象类集合的具体类.

It is worth noting that the documentation is deserializing a Concrete class that contains a collection of Abstract classes.

作为一个实验，尝试创建一个一次性类(具体)，该类具有一个包含抽象对象列表的单一属性，并查看是否可以对其进行序列化和反序列化.

As an experiment try creating a throw-away class (concrete) that has a single property with your list of abstract objects and see if you can serialize and deserialize that.

更新:

我刚刚在 LINQPad 中测试了以下代码:

I just tested the following code in LINQPad:

void Main()
{
    var test = new List<Business>();
    test.Add(new Hotel { Name = "Hilton", Stars = 5 });
    test.Add(new Pool { Name = "Big Splash", Capacity = 500 });

    test.Dump();

    string json = JsonConvert.SerializeObject(test, Newtonsoft.Json.Formatting.Indented, new JsonSerializerSettings
    {
        TypeNameHandling = TypeNameHandling.All
    });

    json.Dump();

    var businesses = JsonConvert.DeserializeObject<List<Business>>(json, new JsonSerializerSettings
    {
        TypeNameHandling = TypeNameHandling.All
    });

    businesses.Dump();
}

// Define other methods and classes here
public abstract class Business
{
    public string Name { get;set; }
}
public class Hotel : Business
{
    public int Stars { get;set; }
}
public class Pool : Business
{
    public int Capacity { get;set;}
}

效果很好.抽象集合序列化为:

It worked perfectly. Abstract collection serialized to:

{
  "$type": "System.Collections.Generic.List`1[[UserQuery+Business, query_jvrdcu]], mscorlib",
  "$values": [
    {
      "$type": "UserQuery+Hotel, query_jvrdcu",
      "Stars": 5,
      "Name": "Hilton"
    },
    {
      "$type": "UserQuery+Pool, query_jvrdcu",
      "Capacity": 500,
      "Name": "Big Splash"
    }
  ]
}

原始集合和反序列化集合匹配.

The original and the deserialized collections matched.

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