asp.net-mvc – Web Api调用返回404错误,GUID作为参数传递

我的ajax调用让我的web.api方法变得麻烦.如果我从api和js中删除了Guid orderId,则调用将其发送给控制器,但是pizza对象为空.如果我在URL中传递Guid,它也会转到控制器但没有披萨.请解释为什么这不起作用或帮助我使其工作.

JS：

var savePizza = function (orderId,pizza) {
    var dataCall = $.ajax(config.savePizzaUrl,{
        data: ko.toJSON({ orderId: orderId,pizza: pizza }),type: "post",contentType: "application/json"
    });

    return Q.when(dataCall);
};

Web Api：

[HttpPost]
    public RequestReturn<Guid> SavePizza(Guid orderId,Pizza pizza)
    {
        return PizzaRequests.SavePizza(orderId,pizza);
    }

JS对象：

var pizza = function (data) {
    this.Id = data.Id;
    this.Size = new size(data.Size);
    this.SizeId = data.SizeId;
    this.Toppings = $.map(data.Toppings,function(item) {return new topping(item);});
};
var topping = function (data) {
    this.Id = data.Id;
    this.Name = data.Name;
    this.Price = data.Price;
};
var size = function (data) {
    this.Id = data.Id;
    this.Name = data.Name;
    this.Price = data.Price;
};

C#对象：

public class Pizza
{
    public Guid Id { get; set; }
    public Guid SizeId { get; set; }
    public Size Size { get; set; }
    public IEnumerable<Topping> Toppings { get; set; }
}
public class Size
{
    public Guid Id { get; set; }
    public string Name { get; set; }
    public double Price { get; set; }
}
public class Topping
{
    public Guid Id { get; set; }
    public string Name { get; set; }
    public double Price { get; set; }
}

JSON Fiddler Post Capture：