Ordering attributes in ASP.NET WebApi response models inheriting href and id from a base class

Question

I have an ASP.NET Web Api 2 project with several response models. In an attempt to create a smaller payload I am offering the user the option to collapse entities to just a id and a href link, which I would like to generate automatically. I would like all my main resource response models to inherit from a base response model that has just the href and id. If I have a resource Foo, this looks something like this:

public class ResourceResponseModel
{
    public string Href { get; private set; }

    public string Id { get; private set; }

    protected ResourceResponseModel(string id)
    {
        Id = id;
    }
}

public class FooModel : ResourceResponseModel
{
    public string Name { get; private set; }

    private ExampleModel (string id, string name)
        : base(id)
    {
        Name = name;
    }

    internal static FooModel From(Foo foo)
    {
        return new FooModel(
            foo.Id,
            foo.Name
        );
    }
}

When my controller is called, this model is serialized with Microsoft.AspNet.Mvc.Json(object data)

This seems to work great, except when I look at the response I end up with, it puts the base class attributes at the end:

{
    "name": "Foo 1",
    "href": "api/abcdefg",
    "id": "abcdefg"
}

Is there an easy way to get the base attributes to appear before the resource attributes?

Answer 1

You can solve this by setting the JsonProperty attribute on you properties and pass in Order.

public class ResourceResponseModel
{
    [JsonProperty(Order = -2)]
    public string Href { get; private set; }

    [JsonProperty(Order = -2)]
    public string Id { get; private set; }

    protected ResourceResponseModel(string id)
    {
        Id = id;
    }
}

Order seems to default to zero and then get sorted from low to high when serialized. Documentation can be found here.