How to post a array of complex objects (that has a array of complex objects) with jQuery

Question

I want to post some Products that has a ID and some Categories with jQuery. But I get a error in: Microsoft.Web.Mvc.DataAnnotations.DataAnnotationsModelBinder.BindProperty (NullReferenceException), when I add the Categories.

Should not the default ModelBinder be able to bind this (without a ActionFilter or custom ModelBinder)?

I tried to apply a ActionFilter (to deserialize) that I found in another SO thread, but it never runs. I have also tried with jQuery.ajaxSettings.traditional = true;, jQuery 1.3.2 and 1.4.2. And in the other examples I have found, they are just posting ID, Name, etc, not another array of complex objects.

Any ideas?

Classes

public class Product
{
    public int ID { get; set; }
    public Category[] Categories { get; set; }
}

public class Category
{
    public int ID { get; set; }
}

HTML

<input id="Product[0]_ID" name="Product[0].ID" type="hidden" value="9" />
<input id="Product[0]_Categories[0]_ID" name="Product[0].Categories[0].ID" type="hidden" value="99" />
<input id="Product[1]_ID" name="Product[1].ID" type="hidden" value="8" />
<input id="Product[1]_Categories[0]_ID" name="Product[1].Categories[0].ID" type="hidden" value="88" />

Controller

[JsonFilter(Parameter = "p")]
public JsonResult GetProductPrice([Bind(Prefix = "Product")] Product[] p)
{
    // TODO: Implement some checking...
    return Json(true);
}

jQuery

$.post(getProductPriceUrl, $("form").serializeArray(), function(data) {
    $("#Price").html(data);
});

JsonFilter

public class JsonFilter : ActionFilterAttribute
{
    public string Parameter { get; set; }
    //public Type JsonDataType { get; set; }

    private JavaScriptSerializer serializer;

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        serializer = new JavaScriptSerializer();

        if (filterContext.HttpContext.Request.ContentType.Equals("application/json"))
        {
            string inputContent;

            using (var sr = new StreamReader(filterContext.HttpContext.Request.InputStream))
            {
                inputContent = sr.ReadToEnd();
            }

            var result = serializer.Deserialize<Product>(inputContent);
            filterContext.ActionParameters[Parameter] = result;
        }
    }
}

POST #1

__RequestVerificationToken=sz%2BLKCzTmdGMrH3TdOYipS5z%2BJ3uVyzBtJRZrruJoUohoGaH2O3DU5%2FcuU6hX1E%2F&Product%5B0%5D.ID=9&Product%5B0%5D.Categories%5B0%5D.ID=99&Product%5B1%5D.ID=8&Product%5B1%5D.Categories%5B0%5D.ID=88

POST #2

__RequestVerificationToken=sz+LKCzTmdGMrH3TdOYipWTERHSdtCvGUhuw/dGIkgSL3rjcSLO7RJJN/rcssVwv&Product[0].ID=9&Product[0].Categories[0].ID=99&Product[1].ID=8&Product[1].Categories[0].ID=88

POST #3

[{"name":"__RequestVerificationToken","value":"sz+LKCzTmdGMrH3TdOYipcqr8WKC2eL7CRS5BZUtwzD60WkqfnjdeAcO3DQg5ss6"},{"name":"Product[0].ID","value":"9"},{"name":"Product[0].Categories[0].ID","value":"99"},{"name":"Product[1].ID","value":"8"},{"name":"Product[1].Categories[0].ID","value":"88"}]