How can I return camelCase JSON serialized by JSON.NET from ASP.NET MVC controller methods?

Question

or, simply put:

JsonConvert.SerializeObject(
    <YOUR OBJECT>, 
    new JsonSerializerSettings 
    { 
        ContractResolver = new CamelCasePropertyNamesContractResolver() 
    });

For instance:

return new ContentResult
{
    ContentType = "application/json",
    Content = JsonConvert.SerializeObject(new { content = result, rows = dto }, new JsonSerializerSettings { ContractResolver = new CamelCasePropertyNamesContractResolver() }),
    ContentEncoding = Encoding.UTF8
};

I found an excellent solution to this problem on Mats Karlsson's blog. The solution is to write a subclass of ActionResult that serializes data via JSON.NET, configuring the latter to follow the camelCase convention:

public class JsonCamelCaseResult : ActionResult
{
    public JsonCamelCaseResult(object data, JsonRequestBehavior jsonRequestBehavior)
    {
        Data = data;
        JsonRequestBehavior = jsonRequestBehavior;
    }

    public Encoding ContentEncoding { get; set; }

    public string ContentType { get; set; }

    public object Data { get; set; }

    public JsonRequestBehavior JsonRequestBehavior { get; set; }

    public override void ExecuteResult(ControllerContext context)
    {
        if (context == null)
        {
            throw new ArgumentNullException("context");
        }
        if (JsonRequestBehavior == JsonRequestBehavior.DenyGet && String.Equals(context.HttpContext.Request.HttpMethod, "GET", StringComparison.OrdinalIgnoreCase))
        {
            throw new InvalidOperationException("This request has been blocked because sensitive information could be disclosed to third party web sites when this is used in a GET request. To allow GET requests, set JsonRequestBehavior to AllowGet.");
        }

        var response = context.HttpContext.Response;

        response.ContentType = !String.IsNullOrEmpty(ContentType) ? ContentType : "application/json";
        if (ContentEncoding != null)
        {
            response.ContentEncoding = ContentEncoding;
        }
        if (Data == null)
            return;

        var jsonSerializerSettings = new JsonSerializerSettings
        {
            ContractResolver = new CamelCasePropertyNamesContractResolver()
        };
        response.Write(JsonConvert.SerializeObject(Data, jsonSerializerSettings));
    }
}

Then use this class as follows in your MVC controller method:

public ActionResult GetPerson()
{
    return new JsonCamelCaseResult(new Person { FirstName = "Joe", LastName = "Public" }, JsonRequestBehavior.AllowGet)};
}

For WebAPI, check out this link: http://odetocode.com/blogs/scott/archive/2013/03/25/asp-net-webapi-tip-3-camelcasing-json.aspx

Basically, add this code to your Application_Start:

var formatters = GlobalConfiguration.Configuration.Formatters;
var jsonFormatter = formatters.JsonFormatter;
var settings = jsonFormatter.SerializerSettings;
settings.ContractResolver = new CamelCasePropertyNamesContractResolver();

I think this is the simple answer you are looking for. It's from Shawn Wildermuth's blog:

// Add MVC services to the services container.
services.AddMvc()
  .AddJsonOptions(opts =>
  {
    opts.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
  });

An alternative to the custom filter is to create an extension method to serialize any object to JSON.

public static class ObjectExtensions
{
    /// <summary>Serializes the object to a JSON string.</summary>
    /// <returns>A JSON string representation of the object.</returns>
    public static string ToJson(this object value)
    {
        var settings = new JsonSerializerSettings
        {
            ContractResolver = new CamelCasePropertyNamesContractResolver(),
            Converters = new List<JsonConverter> { new StringEnumConverter() }
        };

        return JsonConvert.SerializeObject(value, settings);
    }
}

Then call it when returning from the controller action.

return Content(person.ToJson(), "application/json");