c# - 使用 Newtonsoft Json.Net 反序列化为 IEnumerable 类

Question

我有一个项目目前正在使用 Json.Net 来处理像这样的 Json 反序列化类:

public class Foo {
    public Guid FooGuid { get; set; }
    public string Name { get; set; }
    public List<Bar> Bars { get; set; }
}

public class Bar {
    public Guid BarGuid { get; set; }
    public string Description { get; set; }
}

到目前为止一切正常。

为了让迭代更简单，我做了 Foo类(class)工具IEnumerable<Bar>像这样:

public class Foo : IEnumerable<Bar> {
    public Guid FooGuid { get; set; }
    public string Name { get; set; }
    public List<Bar> Bars { get; set; }

    public IEnumerator<Bar> GetEnumerator()
    {
        return Bars.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}

public class Bar {
    public Guid BarGuid { get; set; }
    public string Description { get; set; }
}

但是它无法反序列化对象。该错误令人困惑，因为它说它无法反序列化 FooGuid字段，但删除了 IEnumerable界面再次工作。

在模拟器或设备的 MonoTouch 和 MonoDroid 环境中，问题是相同的。

关于如何让它发挥作用的任何线索？

---

添加代码以重现此问题:

public static class Tests {
    public static void SerializeAndDeserializeFoo() {
        // Serialize and deserialize Foo class
        var element = new Foo
        {
            FooGuid = Guid.NewGuid(),
            Name = "Foo name",
            Bars = new List<Bar> {
                new Bar { BarGuid = Guid.NewGuid(), Description = "Bar description" },
                new Bar { BarGuid = Guid.NewGuid(), Description = "Bar description" },
                new Bar { BarGuid = Guid.NewGuid(), Description = "Bar description" }
            }
        };

        var serializedObject = JsonConvert.SerializeObject(element);
        Console.WriteLine("Serialized Foo element: {0}", serializedObject);

        // Exception if Foo implements IEnumerable
        var deserializedObject = JsonConvert.DeserializeObject<Foo>(serializedObject);
        Console.WriteLine("Foo deserialization worked!");
    }

    public static void SerializeAndDeserializeEnumerableFoo() {
        // Serialize and deserialize Foo class
        var element = new EnumerableFoo
        {
            FooGuid = Guid.NewGuid(),
            Name = "Foo name",
            Bars = new List<Bar> {
                new Bar { BarGuid = Guid.NewGuid(), Description = "Bar description" },
                new Bar { BarGuid = Guid.NewGuid(), Description = "Bar description" },
                new Bar { BarGuid = Guid.NewGuid(), Description = "Bar description" }
            }
        };

        var serializedObject = JsonConvert.SerializeObject(element);
        Console.WriteLine("Serialized EnumerableFoo element: {0}", serializedObject);

        try {
            // Exception if Foo implements IEnumerable
            var deserializedObject = JsonConvert.DeserializeObject<EnumerableFoo>(serializedObject);
            Console.WriteLine("EnumerableFoo deserialization worked!");
        }
        catch (Exception e){
            Console.WriteLine("EnumerableFoo deserialization failed!");
            throw;
        }
    }
}

public class EnumerableFoo : IEnumerable<Bar> {
    public Guid FooGuid { get; set; }
    public string Name { get; set; }
    public List<Bar> Bars { get; set; }

    public IEnumerator<Bar> GetEnumerator()
    {
        return Bars.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}

public class Foo {
    public Guid FooGuid { get; set; }
    public string Name { get; set; }
    public List<Bar> Bars { get; set; }
}

public class Bar {
    public Guid BarGuid { get; set; }
    public string Description { get; set; }
}

示例项目:https://www.dropbox.com/s/27i58aiz71dylkw/IEnumerableJson.zip

Answer 1

来自Json.Net documentation :

IEnumerable, Lists and Arrays

.NET lists (types that inherit from IEnumerable) and .NET arrays are converted to JSON arrays. Because JSON arrays only support a range of values and not properties, any additional properties and fields declared on .NET collections are not serialized. In situations where a JSON array is not wanted the JsonObjectAttribute can be placed on a .NET type that implements IEnumerable to force the type to be serialized as a JSON object instead.

换句话说，因为你的类实现了IEnumerable<T> , Json.Net认为是一个列表。为了解决这个问题，只需用 [JsonObject] 装饰你的类(class)属性。这将强制 Json.Net 将其序列化和反序列化为普通类，这正是您在本例中想要的。

[JsonObject]
public class EnumerableFoo : IEnumerable<Bar>
{
    ...
}