如何从C＃Web API DbSet获取实际对象？

Question

I'm trying to get a list of 'recent' donuts that have been added to the box (database) since I last checked. I'm a fatty and want some delicious noms. The problem: the server is giving me JSON that is full of $ids and $refs, so my list ends up being one object, with the rest as null (because response.Content.ReadAsAsync doesn't handle the references).

Please help. I just want some straight up donut objects man. None of this $ref icing or $id filling.

My server side controller:

public class DonutController : ApiController
{
    private DonutEntities db = new DonutEntities();

    // GET api/PackageEvent/since/{datetime}
    public IEnumerable<Donut> GetDonutsSince([FromUri] String datetime) {
        List<Donut> donuts = null;
        DateTime dt = DateTime.Parse(datetime);

        //return db.Donuts.Where(d => d.When > dt).AsEnumerable();

        String sql = @"
            SELECT *
            FROM Donuts
            WHERE [Donuts].[When] > CAST(@datetime AS DATETIME)
        ";

        object[] parameters = new object[] {
            new SqlParameter("@datetime", DateTime.Parse(datetime).ToString(CultureInfo.InvariantCulture))
        };

        List<Donut> results = db.Donuts.SqlQuery(sql, parameters).ToList();
        if (results.Any()) {
            donuts = results;
        }

        return donuts.AsEnumerable();
    }
}

My client side request method:

    public static IEnumerable<Donut> GetDonutsSince(DateTime dt) {
        HttpClient api = new HttpClient { BaseAddress = new Uri("http://localhost:55174/api/") };
        api.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

        String url = "Donut/since?datetime=" + dt;
        HttpResponseMessage response = api.GetAsync(url).Result;

        Console.WriteLine(response.Content.ReadAsStringAsync().Result);
        // outputs the raw json with $ids and $refs

        IEnumerable<Donut> donuts = response.Content.ReadAsAsync<IEnumerable<Donut>>().Result;

        return donuts;
    }

Answer 1

So it turns out that the solution was to use Json.NET . It handles the $id and $ref attributes, and actually creates a list populated with objects.

New client side request method:

public static IEnumerable<Donut> GetDonutsSince(DateTime dt) {
    HttpClient api = new HttpClient { BaseAddress = new Uri("http://localhost:55174/api/") };
    api.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    String url = "Donut/since?datetime=" + dt;
    HttpResponseMessage response = api.GetAsync(url).Result;
    String responseContent = response.Content.ReadAsStringAsync().Result;

    IEnumerable<Donut> events = JsonConvert.DeserializeObject<IEnumerable<Donut>>(responseContent);

    return donuts;
}