Web API does not return JSON

Question

made a web api c# where by default returns xml, tried from various internet methods turn this return to json but when I make a request keeps coming in xml, someone could help?

method giving the result:

 // GET: api/OINV/5
    [ResponseType(typeof(OINV))]
    public IHttpActionResult GetOINV(int id)
    {
        OINV oINV = db.OINV.Find(id);
        if (oINV == null)
        {
            return NotFound();
        }

        return Ok(oINV);
    }

webapiconfig.Cs

 public static void Register(HttpConfiguration config)
    {
        // Web API configuration and services
        // Web API routes
        config.Formatters.JsonFormatter.SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html"));
        config.MapHttpAttributeRoutes();
        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );


    }

Answer 1

You really have nothing to worry about, ASP.NET Web API 2 with the Framework 4.X will serialize the answers as much as XML, how much JSON as defined in the request. You should not worry about how this content is appearing in the browser because the Web API is not presenting content for a user reading, but rather serving as an interface for communication between applications.

Microsoft documentation

That is by default he is already attending clients who intend to deserialize the content both in XML how much JSON. But, if you want to restrict your application to return only in JSON format you can do as suggested by @Barbetta and remove Mediatype from xml from the formatters list.

Now, if the issue is just for you to view the data in the browser for testing and "documentation" you can implement features that are specialized for this, such as the Swagger.

But what I would really recommend, once you are starting a new application, is to already work with the version of ASP.Net Core that will only bring you benefits (tutorial).

See the example below:

Answer 2

One option is to remove the SupportedMediaType XML

public static void Register(HttpConfiguration config)
{
    //Outras Configurações
    config.Formatters.XmlFormatter.SupportedMediaTypes
        .Remove(config.Formatters.XmlFormatter.SupportedMediaTypes.FirstOrDefault(t => t.MediaType == "application/xml"));
}

Answer 3

Try adding the following lines to the method Register:

 config.Formatters.Clear();
 config.Formatters.Add(new JsonMediaTypeFormatter());

I saw a guy with the same problem here at stackoverflow and he did it: How do I get ASP.NET Web API to Return JSON Instead of XML using Chrome?

It erases all web api formatters and then adds support for json formatting