Setting the default JSON serializer in ASP.NET MVC

Question

I'm working on an existing application that has been partially converted over to MVC. Whenever a controller responds with a JSON ActionResult, the enums are sent as numbers opposed to the string name. It sounds like the default serializer should be JSON.Net, which should be sending the enums over as their names opposed to the integer representation, but that's not the case here.

Am I missing a web.config setting that sets this as the default serializer? Or is there another setting that needs to be changed?

Answer 1

In ASP.Net MVC4 the default JavaScript serializer which is used in the JsonResult class is still the JavaScriptSerializer (you can check it in the code)

I think you have confused it with the ASP.Net Web.API where JSON.Net is the default JS serializer but MVC4 doesn't use it.

So you need to configure JSON.Net to work with MVC4 (basically you need to create your own JsonNetResult), there are plenty of articles about it:

• ASP.NET MVC and Json.NET
• Using JSON.NET as the default JSON serializer in ASP.NET MVC 3 - is it possible?

If you also want to use JSON.Net for controller action parameters so during the model binding then you need write your own ValueProviderFactory implementation.

And you need to register your implementation with:

ValueProviderFactories.Factories
    .Remove(ValueProviderFactories.Factories
                                  .OfType<JsonValueProviderFactory>().Single());
ValueProviderFactories.Factories.Add(new MyJsonValueProviderFactory());

You can use the built in JsonValueProviderFactory as an example or this article: ASP.NET MVC 3 – Improved JsonValueProviderFactory using Json.Net