How to store JSON in an entity field with EF Core?

Question

I am creating a reusable library using .NET Core (targeting .NETStandard 1.4) and I am using Entity Framework Core (and new to both). I have an entity class that looks like

Answer 1

The comment by @Métoule:

Be careful with this approach: EF Core marks an entity as modified only if the field is assigned to. So if you use person.Addresses.Add, the entity won't be flagged as updated; you'll need to call the property setter person.Addresses = updatedAddresses.

made me take a different approach so that this fact is obvious: use Getter and Setter methods, rather than a property.

public void SetExtendedData(JObject extendedData) {
    ExtendedData = JsonConvert.SerializeObject(extendedData);
    _deserializedExtendedData = extendedData;
}

//just to prevent deserializing more than once unnecessarily
private JObject _deserializedExtendedData;

public JObject GetExtendedData() {
    if (_extendedData != null) return _deserializedExtendedData;
    _deserializedExtendedData = string.IsNullOrEmpty(ExtendedData) ? null : JsonConvert.DeserializeObject(ExtendedData);
    return _deserializedExtendedData;
}

You could theoretically do this:

campaign.GetExtendedData().Add(something);

But it's much more clear that That Doesn't Do What You Think It Does™.

If you're using database-first and using some kind of class auto-generator for EF, then the classes will usually be declared as partial, so you can add this stuff in a separate file that won't get blown away the next time you update your classes from your database.