Returning JSON from a JsonResult method in MVC controller

Question

I am trying to populate a ComboBox (Telerik RAD COmboBox) in a test ASP.NET MVC3 app.

I have defined the ComboBox on my ASPX page and in the controller I have defined the action call that returns a JsonResult.

The problem I am having is that the Web Service I am using already returns the resultset as a JSON string. How can I pass the response from the Webservice directly.

Here is the snippets of code: ASPX page:

<% Html.Telerik().ComboBox()
                       .Name("cbRefTables")
                       .DataBinding(b => b
                           .Ajax()
                           .Select("GetCALMdata","Common")                    
                       )
                       .Render();
                %>

Controller: called CommomController

    public JsonResult GetCALMdata()
    {
        CALMwsP.wsCALMSoapClient wsC = new CALMwsP.wsCALMSoapClient("wsCALMSoap");
        string resultset = wsC.GetRefTables("P_1", "P_2", "P_3", "P_4");

        return ??; -- I want to return resultset which is already formatted. 
    }

score 27 · Answer 1 · answered May 05 '11 at 17:01

27

If using ASP.NET MVC 2 or higher:

return Json(resultset, JsonRequestBehavior.AllowGet);

answered May 05 '11 at 17:01

alexl

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3
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29

That is what I originally had, however I get the following error: Microsoft JScript runtime error: 'Selected' is null or not an object – MAB May 05 '11 at 17:07
1

Well, that error isn't coming out of the controller. So your issue is with how you are handling the JSON. – Mike Brind May 05 '11 at 17:23
most likely that error is from the combobox, it doesn't know what the default selected item should be – curtisk May 05 '11 at 17:28
3

What is the using reference? – Serj Sagan Feb 08 '13 at 04:40

score 20 · Accepted Answer · answered May 05 '11 at 17:44

20

If the resultset string is already JSON (and not wrapped in any XML), then you'd want to return a ContentResult with exactly that string as the content:

public ContentResult GetCALMdata()
{
    CALMwsP.wsCALMSoapClient wsC = new CALMwsP.wsCALMSoapClient("wsCALMSoap");
    string resultset = wsC.GetRefTables("P_1", "P_2", "P_3", "P_4");

    return Content(resultset, "application/json");
}

You don't want to use JsonResult or the Json() helper in this case, because that's going to end up re-serializing your JSON.

answered May 05 '11 at 17:44

Dave Ward

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The additional contentType parameter being set to `application/json` is what I needed. I was doing the Json serialization with Newtonsoft.Json rather than the built in one because I wanted some of serialization customisation it can do. – Matt Kemp Jul 28 '21 at 01:38

score 6 · Answer 3 · answered May 05 '11 at 16:58

6

if I correctly understood you should use the Json() method

return Json(resultset);

answered May 05 '11 at 16:58

Sergey K

4,071
2
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34

9

What is the using reference? – Serj Sagan Feb 08 '13 at 04:40

Jeremy Thompson · Answer 4 · 2018-06-12T04:33:11.167

1

The individual Json Method:

return Json(resultset);

It needs the System.Web.Http DLL and the namespace is System.Web.Http.Results.

Or Website wide put this line in the WebApiConfig.cs

config.Formatters.JsonFormatter.SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html"));

edited Jun 12 '18 at 04:33

answered Jun 12 '18 at 04:25

Jeremy Thompson

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+ for including DLL name and namespace. – FrenkyB Jul 23 '20 at 12:32

score 1 · Answer 5 · answered Jan 01 '20 at 00:49

In MVC 5 and possibly below you can do something like this:

            var dict = new Dictionary<string, string>
            {
                { "name", "Foobar" },
                { "url", "admin@foobar.com" }
            };

            var json = new JsonResult()
            {
                Data = dict
            };

Returning JSON from a JsonResult method in MVC controller

5 Answers5

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