#nullable enable

​

using System;

using System.Linq;

using System.Text.Json;

using System.Text.Json.Serialization;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var outerThing = new OuterObject(new Thing(Guid.NewGuid(), "outer object thing", null));

        var serializedOuterThing = JsonSerializer.Serialize(outerThing);

        Console.WriteLine($"Serialized outer thing: {serializedOuterThing}");

        var deserializedOuterThing = JsonSerializer.Deserialize<OuterObject>(serializedOuterThing);

        // this works

        Console.WriteLine($"Outer thing Id: {deserializedOuterThing.Thing.Id} Name: {deserializedOuterThing.Thing.Name}");

        var containerThing = new ContainerObject(new[] { new Thing(Guid.NewGuid(), "container thing", null) });

        var serializedContainerThing = JsonSerializer.Serialize(containerThing);

        Console.WriteLine($"Serialized container thing: {serializedContainerThing}");

        var deserializedContainerThing = JsonSerializer.Deserialize<ContainerObject>(serializedContainerThing);

        // this works

        Console.WriteLine($"Container thing Id: {deserializedContainerThing.Things.First().Id} Name: {deserializedContainerThing.Things.First().Name}");

        var thingByItself = new Thing(Guid.NewGuid(), "thing by itself", null);

        var serializedThingByItself = JsonSerializer.Serialize(thingByItself);

        Console.WriteLine($"Serialized thing by itself: {serializedThingByItself}");

        var deserializedThingByItself = JsonSerializer.Deserialize<IThing>(serializedThingByItself);

        // this doesn't work

        Console.WriteLine($"Container thing Id: {deserializedThingByItself.Id} Name: {deserializedThingByItself.Name}");

    }

}

​

[JsonDerivedType(typeof(Thing), typeDiscriminator: 1)]

public interface IThing

{

    public Guid Id { get; }

    public string Name { get; }

}

​

public record Thing(Guid Id, string Name, string? Description) : IThing;

​

​

public record OuterObject(IThing Thing);

​

public record ContainerObject(IReadOnlyCollection<IThing> Things);