JSON.NET (by Newtonsoft) has great support for serializing and deserializing complex objects.
I am curious about using System.Text.Json instead of JSON.NET and I am not able to find a good tutorial on the internet.
The .NET 7 preview has support for deserializing polymorphic objects. Here is an example using .NET 7 preview and C# 11:
// _To run it you will need net7 preview and c# 11_
using System.Text.Json.Serialization;
var testPolymorphism = new TestPolymorphysm()
{
Animals = new List<Animal>()
{
new Fish() {
Id = "fish1",
Name = "GoldFish",
Action = new ActionSwim() { DistanceSwam = 10 }
},
new Dog() {
Id = "dog1",
Name = "Tom",
Action = new ActionRun() { DistanceRan = 50 }
}
}
};
// serialize
var jsonSerialized = System.Text.Json.JsonSerializer.Serialize(testPolymorphism);
Console.WriteLine(jsonSerialized);
// deserialize
var clonePolymorphysm = System.Text.Json.JsonSerializer.Deserialize<TestPolymorphysm>(jsonSerialized);
Console.WriteLine(clonePolymorphysm);
// === MODELS ===
class TestPolymorphysm
{
public List<Animal> Animals { get; set; } = new();
}
[JsonDerivedType(derivedType: typeof(Dog), typeDiscriminator: "foo1")]
[JsonDerivedType(derivedType: typeof(Fish), typeDiscriminator: "foo2")]
abstract class Animal
{
public required string Id { get; set; }
public required string Name { get; set; }
}
class Dog : Animal
{
public required IAction Action { get; set; }
public AnimalType ExtensionType => AnimalType.Dog;
}
class Fish : Animal
{
public required IAction Action { get; set; }
public AnimalType ExtensionType => AnimalType.Fish;
}
[JsonDerivedType(derivedType: typeof(ActionSwim), typeDiscriminator: "foo3")]
[JsonDerivedType(derivedType: typeof(ActionRun), typeDiscriminator: "foo4")]
interface IAction { }
class ActionSwim : IAction
{
public required int DistanceSwam { get; set; }
}
class ActionRun : IAction
{
public required int DistanceRan { get; set; }
}
public enum AnimalType
{
Fish,
Dog
}
Anyways this code works thanks to JsonDerivedType attributes but I am not sure why it works. Why is it that if I remove the typeDiscriminators foo1, foo2, foo3 and foo4 it does not work? I want to make sure I understand how it works before I use it.
