Return Entity Framework Objects as JSON

Question

I try to return Entity Framework Objects as Json with the following method in my Controller:

  public JsonResult EventList() {
        var results = from s in db.Events
                      select new
                      {
                          OrderID = s.EventID,
                          OrderTitle =s.EventType,
                          OrderDate = s.Title
                      };

return Json(results);
}

I get a server error 500 when entering the page /events/EventList/. Also a Jquery get request returns no data. What is the correct way to return the results in Json format?

Update:

This seems to work. But I need results from the database.

   public ActionResult EventList() {

        Event test = new Event
        {
            EventID = 1,
            Title = "test",
            Description = "test"
        };

        return Json(new { event = test }, JsonRequestBehavior.AllowGet);
    }

Are you making a GET call? If so, you need return Json(results, JsonRequestBehavior.AllowGet); — user3559349
– user3559349, Commented Oct 20, 2015 at 12:04
Try to add .ToArray() to results: return Json(results.ToArray()) — Kirill Bestemyanov
– Kirill Bestemyanov, Commented Oct 20, 2015 at 12:07
@StephenMuecke if I add JsonRequestBehavior.AllowGet); I get the HTML of the index view as result — Citizen SP
– Citizen SP, Commented Oct 20, 2015 at 12:10
@JasonB, What you you mean the HTML? - your returning json, not a view. — user3559349
– user3559349, Commented Oct 20, 2015 at 12:13

Craig · Accepted Answer · 2019-03-21 13:31:00Z

Edit: 2019

This answer still gets upvotes - if you're going down this road I really really suggest you just save yourself the future headaches and use a DTO. Serializing your entity is probably faster for now but (and I have learned this the hard way) - you are going to hate yourself in a years time.

New answer - updated for 2018:

The original answer below will work every time and if you're using lazy loading, it may still be the best solution. Without lazy loading though, you can do the following with Newtonsoft.JSON:

var settings = new JsonSerializerSettings()
    {
        ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
        Error = (sender, args) =>
        {
            args.ErrorContext.Handled = true;
        },
    };

using(var context = new myContext())
{
    var myEntity = myContext.Foos.First();
    return JsonConvert.SerializeObject(myEntity, settings);
}

Which basically will serialize anything that's been included in the entity framework request, while ignoring any errors and reference loops.

The drawback to this method is that controlling what gets serialized is harder and if you're performance conscious, you may need to start decorating your generated Entity Framework classes with a pattern like

// a new partial class extending the Foo generated class, allowing us to apply an interface
[MetadataType(typeof(IFooMetaData))]
public partial class Foo : IFooMetaData
{
}

// meta data interface, forcing json ignore on Foo.Bars
public interface IFooMetaData
{
    [JsonIgnore]
    ICollection<Bar> Bars {get;set;}
}

Original answer - 2015:

Can get this response:

[
{
"OrderID": 1
},
{
"OrderID": 2
},
{
"OrderID": 3
}
]

from this:

    public JsonResult Test()
    {
        var events = new List<Event>()
        {
            new Event() {EventId = 1},
            new Event() {EventId = 2},
            new Event() {EventId = 3}
        };


        var results = events.Select(e => new
        {
            OrderID = e.EventId
        }).ToList();

        return new JsonResult() { Data = results, JsonRequestBehavior = JsonRequestBehavior.AllowGet };
    }

So yours should be something like

    public JsonResult Test()
    {
        var results = db.Events.Select(e => new
        {
            OrderID = e.EventId
        }).ToList();

        return new JsonResult() { Data = results, JsonRequestBehavior = JsonRequestBehavior.AllowGet };
    }

edit

re-posted with tested code

It redirects to the default error page (views/shared/error.chtml)

Yunnosch · Accepted Answer · 2021-04-26 21:01:48Z

0

In the controller: for example

List<categories> data = context.categories.toList();  //to here all right

now, the problem with the serialization for "data" for send the json result... i just used a struct to replace the List how???

just watch:

in the same controller ...

   struct categories_struct{
   public fieldname {get;set;}
   //the same for others firelds (same the model)
  }

now, in the ActionResult or maybe in jsonresult :

  List<categorias> data = contexto.categorias.ToList();  //I use the EF
 List<catego> data2 = new List<catego>();              //create the struct var

        foreach (categorias item in data)    //fill the struct with data
        {
            catego item2 = new catego();
            item2.codcat = item.codcat;
            item2.nomcat = item.nombrecat;
            item2.descripcion = item.descripcion;
            data2.Add(item2);
        }

        //here, Data contains all data2
        return Json(new { Data = data2 }, JsonRequestBehavior.AllowGet);

in the view:

$.ajax({
            url: "/Categorias/getTabla",
              dataType: "JSON",
            type: "POST",
        }).done(function (respuesta) {
            var data = JSON.parse(JSON.stringify(respuesta));
            console.log(respuesta);
            alert('exito');
        }).fail(function () {
            alert('oh no, again!');
        });

///

is my solution for this problem

edited Apr 26, 2021 at 21:01

Yunnosch

26.8k9 gold badges46 silver badges66 bronze badges

answered Apr 26, 2021 at 20:47

Edmundo González

1

1 Comment

Yunnosch Over a year ago

Typing laughing into the answer degrades the impression of helpfulness. Also, please do the job hunting the way StackOverflow supports, not by sneaking it into answers.

Collectives™ on Stack Overflow

Return Entity Framework Objects as JSON

2 Answers 2

2 Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related