Default model binder and complex types that include a list

Question

Hi All

I'm using RC1 of ASP.NET MVC.

I'm trying to extend Phil Haack's model binding example. I'm trying to use the default model binder to bind the following object:

public class ListOfProducts
{
    public int Id { get; set; }
    public string Title{ get; set; }
    List<Product> Items { get; set; }
}

public class Product
{
    public string Name { get; set; }
    public decimal Price { get; set; }
}

I'm using the code from Phil's example with some alterations:

Controller:

using System.Collections.Generic;
using System.Web.Mvc;

namespace TestBinding.Controllers
{
    [HandleError]
    public class HomeController : Controller
    {
     public ActionResult Index()
     {
      ViewData["Message"] = "Welcome to ASP.NET MVC!";

      return View();
     }

     //Action method on HomeController
     public ActionResult UpdateProducts(ListOfProducts productlist)
     {
      return View(productlist);
     }
    }

    public class Product
    {
     public string Name { get; set; }
     public decimal Price { get; set; }
    }

    public class ListOfProducts
    {
     public int Id { get; set; }
     public string Title { get; set; }
     List<Product> Items { get; set; }
    }
}

View:

<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %>

<asp:Content ID="indexHead" ContentPlaceHolderID="head" runat="server">
    <title>Home Page</title>
</asp:Content>

<asp:Content ID="indexContent" ContentPlaceHolderID="MainContent" runat="server">
    <form method="post" action="/Home/UpdateProducts">
     <input type="text" name="productlist.id" value="99" />
     <input type="text" name="productlist.Title" value="SomeTitle" />

     <input type="hidden" name="productlist.Index" value="0" />
     <input type="text" name="productlist.items[0].Name" value="Beer" />
     <input type="text" name="productlist.items[0].Price" value="7.32" />

     <input type="hidden" name="productlist.Index" value="1" />
     <input type="text" name="productlist.Items[1].Name" value="Chips" />
     <input type="text" name="productlist.Items[1].Price" value="2.23" />

     <input type="hidden" name="productlist.Index" value="2" />
     <input type="text" name="productlist.Items[2].Name" value="Salsa" />
     <input type="text" name="productlist.Items[2].Price" value="1.23" />

     <input type="submit" />
    </form>
</asp:Content>

My problem is that the simple types (Id and Title) appears in the productlist object, but not the List. So:

• Is my code bad (wouldn't be surprised)?
• Can the default model binder handle the ListOfProducts objects?
• If the default model binder won't handle this type of object what do I need to do (examples if possible)?

Thanks in advance.

Answer 1

Starting with RC 1:

• Hidden Index is no longer required
• The number in [] must start with 0 and must ascend.

Your numbering looks OK.

Also, I noticed that you used different casing on your items property name. That should not make a difference, but it's worth checking.

Answer 2

To answer my own question:

I'm a dummy!

My example doesn't work because the Items property of the ListOfProducts class is not public:

public class ListOfProducts
{
    public int Id { get; set; }
    public string Title{ get; set; }
    List<Product> Items { get; set; }
}

I changed:

List<Product> Items { get; set; }

to:

public List<Product> Items { get; set; }

and my code then worked.

To conclude the default model binder does work with types that contain properties of type List.