C#Json.net不可变类 [英] c# Json.net immutable class

问题描述

我看到了其他类似的问题/答案，但均未显示两者序列化/反序列化

I saw other similar questions/answers but none show both serialization/deserialization

示例:

public class DeepNested {
    [JsonProperty]
    int X { get; }

    [JsonProperty]
    int Y { get; }

    public DeepNested(int x, int y) { X = x; Y = y; }

    [JsonConstructor]
    public DeepNested(DeepNested dn) { X = dn.X; Y = dn.Y; }
}

public class Nested {
    [JsonProperty]
    DeepNested DN { get; }

    [JsonProperty]
    int Z { get; }

    [JsonProperty]
    int K { get; }

    [JsonConstructor]
    public Nested(DeepNested dn, int z, int k) { DN = new DeepNested(dn); Z = z; K = k; }
}

public class C {
    [JsonProperty]
    Nested N { get; }

    [JsonConstructor]
    public C(Nested n) { N = n; }
}

class Program {
    static void Main(string[] args) {
        var deepNested = new DeepNested(1,2);
        var nested = new Nested(deepNested, 3, 4);
        C c = new C(nested);
        string json = JsonConvert.SerializeObject(c);
        C c2 = JsonConvert.DeserializeObject<C>(json);
        Console.WriteLine(json);
    }
}

我在DeepNested.DeepNested(DeepNested dn)

System.NullReferenceException: 'Object reference not set to an instance of an object.'

调试器显示dn是null

除非我缺少某些东西，否则这似乎是Json.NET的严重限制?

This seems be a serious limitation of Json.NET unless I'm missing something ?

推荐答案

@IpsitGaur是正确的，通常，您应该具有默认的公共构造函数和可公共访问的属性(可变).但是JSON.Net是一个非常强大的工具！

@IpsitGaur is right, commonly you should have a default public constructor and publicly accessable properties (mutable). But JSON.Net is a very powerfull tool!

如果您需要处理非默认构造函数，则可以使用 JsonConstructorAttribute .对于您的代码，示例可能像这样:

If you need to handle non-default constructor, you may use JsonConstructorAttribute. For your code, example may be like this:

public class Nested
{
    public int X { get; }
    public int Y { get; }

    [JsonConstructor]
    Nested(int x, int y) { X=x; Y=y; }
}

public class C
{
    public Nested N { get; }

    [JsonConstructor]
    public C(Nested n) { N = n; }
}

var c1 = new C(new Nested(1, 2));
var json = JsonConvert.SerializeObject(c1); // produce something like "{\"n\":{\"x\":1,\"y\":2}}";
var c2 = JsonConvert.DeserializeObject<C>(json);

这篇关于C#Json.net不可变类的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！