Using JSON.NET to return ActionResult [duplicate]

Question

This question already has answers here:

Json.Net And ActionResult (2 answers)

Closed 5 years ago.

I'm trying to write a C# method that will serialize a model and return a JSON result. Here's my code:

    public ActionResult Read([DataSourceRequest] DataSourceRequest request)
    {
        var items = db.Words.Take(1).ToList();
        JsonSerializerSettings jsSettings = new JsonSerializerSettings();
        jsSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
        var converted = JsonConvert.SerializeObject(items, null, jsSettings);
        return Json(converted, JsonRequestBehavior.AllowGet);
    }

I got the following JSON result when I go to Words/Read in Chrome:

"[{\"WordId\":1,\"Rank\":1,\"PartOfSpeech\":\"article\",\"Image\":\"Upload/29/1/Capture1.PNG\",\"FrequencyNumber\":\"22038615\",\"Article\":null,\"ClarificationText\":null,\"WordName\":\"the | article\",\"MasterId\":0,\"SoundFileUrl\":\"/UploadSound/7fd752a6-97ef-4a99-b324-a160295b8ac4/1/sixty_vocab_click_button.mp3\",\"LangId\":1,\"CatId\":null,\"IsActive\":false}

I think the \" escaped quotes are a problem that occurs when you double serialize an object. From other questions: WCF JSON output is getting unwanted quotes & backslashes added

It definitely looks like I'm double serializing my object, since I first serialize using JSON.NET and then pass my result into the Json() function. I need to manually serialize to avoid referenceloops, but I think my View needs an ActionResult.

How can I return an ActionResult here? Do I need to, or can I just return a string?

Answer 1

I found a similar stackoverflow question: Json.Net And ActionResult

The answer there suggested using

return Content( converted, "application/json" );

That seems to work on my very simple page.

Answer 2

Instead of serializing using JSON.NET and then calling Json(), why not instead override the Json() method in your controller (or perhaps a base controller to enhance its re-usability)?

This is pulled from this blog post.

In your controller (or base controller):

protected override JsonResult Json(
        object data,
        string contentType,
        System.Text.Encoding contentEncoding,
        JsonRequestBehavior behavior)
{
    return new JsonNetResult
    {
        Data = data,
        ContentType = contentType,
        ContentEncoding = contentEncoding,
        JsonRequestBehavior = behavior
    };
}

And the definition for JsonNetResult:

public class JsonNetResult : JsonResult
{
    public JsonNetResult()
    {
        Settings = new JsonSerializerSettings
        {
            ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
        };
    }

    public JsonSerializerSettings Settings { get; private set; }

    public override void ExecuteResult(ControllerContext context)
    {
        if (context == null)
            throw new ArgumentNullException("context");
    if (this.JsonRequestBehavior == JsonRequestBehavior.DenyGet
        && "GET".Equals(
                context.HttpContext.Request.HttpMethod,
                StringComparison.OrdinalIgnoreCase))
    {
        throw new InvalidOperationException("JSON GET is not allowed");
    }


        HttpResponseBase response = context.HttpContext.Response;
        response.ContentType =
            string.IsNullOrEmpty(this.ContentType) ? "application/json" : this.ContentType;

        if (this.ContentEncoding != null)
            response.ContentEncoding = this.ContentEncoding;
        if (this.Data == null)
            return;

        var scriptSerializer = JsonSerializer.Create(this.Settings);

        using (var sw = new StringWriter())
        {
            scriptSerializer.Serialize(sw, this.Data);
            response.Write(sw.ToString());
        }
    }
}

By doing this, when you call Json() in your controller, you will automatically get the JSON.NET serializing you want.