Question

Here’s the setup:

I have some MVC Controllers that are intended to be consumed by jQuery ajax requests. A normal request would seem somewhat like this:

$.ajax("/Solicitor/AddSolicitorToApplication", {
    data: putData,
    type: "POST", contentType: "application/json",
    success: function (result) {
       //My success callback
        }
    }
});

My controller looks like this:

[HttpPost]
public ActionResult InsertLoanApplication(MortgageLoanApplicationViewModel vm)
{
   var mortgageLoanDTO = vm.MapToDTO();
   return Json(_mortgageLoanService.UpdateMortgageLoanApplication(mortgageLoanDTO),   JsonRequestBehavior.DenyGet);
}

This works perfectly fine with most objects passed to the controller, except that in this specific case one of the properties of the object being passed needs to be deserialized in a specific way.

I’ve added a JsonConverter that I’ve used previously with the MVC4 Web API, but in this case I need to apply it to regular mvc controllers.

I tried registering the JsonConverter in my global.asax like this:

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.Converters.Add(new GrizlyStringConverter());

But so far haven’t been able to deserialize the object.

Answer 1

You should replace the built-in JsonValueProviderFactory class with a custom one if you want to use Json.NET when binding JSON requests to view models.

You could write one as shown in this gist:

public sealed class JsonDotNetValueProviderFactory : ValueProviderFactory
{
    public override IValueProvider GetValueProvider(ControllerContext controllerContext)
    {
        if (controllerContext == null)
        {
            throw new ArgumentNullException("controllerContext");
        }

        if (!controllerContext.HttpContext.Request.ContentType.StartsWith("application/json", StringComparison.OrdinalIgnoreCase))
        {
            return null;
        }

        using (var reader = new StreamReader(controllerContext.HttpContext.Request.InputStream))
        {
            var bodyText = reader.ReadToEnd();

            return String.IsNullOrEmpty(bodyText)
                ? null :
                new DictionaryValueProvider<object>(
                    JsonConvert.DeserializeObject<ExpandoObject>(
                        bodyText,
                        new ExpandoObjectConverter()
                    ),
                    CultureInfo.CurrentCulture
                );
        }
    }
}

and then replace the built-in with your custom one in Application_Start:

ValueProviderFactories.Factories.Remove(
    ValueProviderFactories
        .Factories
        .OfType<JsonValueProviderFactory>()
        .FirstOrDefault()
);
ValueProviderFactories.Factories.Add(new JsonDotNetValueProviderFactory());

That’s it. Now you are using Json.Net instead of the JavaScriptSerializer for the incoming JSON requests.