C#•2y ago

❔ Serialize inheriting types as a parent type

Hi! I have this class to group all localization types

public class Location {
}

public class Location {
}

sample localization type

public class Address : Location {
    public string CityName { get; }

    public Address(string cityName) {
        CityName = cityName;
    }

    public override string ToString() {
        return CityName;
    }
}

public class Address : Location {
    public string CityName { get; }

    public Address(string cityName) {
        CityName = cityName;
    }

    public override string ToString() {
        return CityName;
    }
}

and when i try to serialize it

public class PersistentData {
    public Location? Location { get; set; }
}

public class PersistentData {
    public Location? Location { get; set; }
}

            data.Location = new Address("Kraków");
            string json = JsonSerializer.Serialize(data);
            File.WriteAllText(storageFilePath, json);

            data.Location = new Address("Kraków");
            string json = JsonSerializer.Serialize(data);
            File.WriteAllText(storageFilePath, json);

I get

{
    "Location": {}
}

{
    "Location": {}
}

5 Replies

Indeed•2y ago

I guess its due to Location not having any properties but how can i go around it

Hugh•2y ago

If you add this attribute on Location, you'll get what you want:

[JsonDerivedType(typeof(Address), "Address")]
public class Location {
}

[JsonDerivedType(typeof(Address), "Address")]
public class Location {
}

This will add "$type":"Address", which will be referenced when deserializing If you ever want to be able to serialize an Address (that is specifically typed as such) and then deserialize it as a Location, you'll have to add the same attribute to the Address class

Indeed•2y ago

Thank you! It was exactly what I needed. Interesting how it is done. I was able to apply it to all derived classes ❤️

Hugh•2y ago

👍

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Serialize inheriting types as a parent type