How to Update using MVC2 RC2 - asp.net-mvc

Question

I am trying to edit a record. I have the default route.
When I click the submit button I get an exception on the UpdateModel line:
The model of type 'MyProject.Mvc.Models.Product' could not be updated.
On the page the validation of the ProductId field is prompting the value is invalid:
The value '9' is invalid. 9 is the id of the record I am trying to edit. What could be wrong?
public ActionResult Edit(int id)
{
Product product = productRepository.GetProduct(id);
return View(new ProductFormViewModel(product));
}
[HttpPost]
public ActionResult Edit(int id, FormCollection productFormViewModel)
{
Product product = productRepository.GetProduct(id);
try
{
// TODO: Add update logic here
UpdateModel(product, "Product");
productRepository.Save();
return RedirectToAction("Index");
}
catch (Exception ex)
{
return View(new ProductFormViewModel(product));
}
}
If I change the update model line to:
UpdateModel(product);
then no exception is thrown and the data is not updated in the database.
[Edit]
I am using Entity Framework
namespace MyProject.Mvc.Models
{
[MetadataType(typeof(ProductMetaData))]
public partial class Product
{
public Product()
{
// Initialize Product
this.CreateDate = System.DateTime.Now;
}
}
public class ProductMetaData
{
[Required(ErrorMessage = "Product name is required")]
[StringLength(50, ErrorMessage = "Product name must be under 50 characters")]
public object ProductName { get; set; }
[Required(ErrorMessage = "Description is required")]
public object Description { get; set; }
}
public class ProductFormViewModel
{
public Product Product { get; private set; }
public ProductFormViewModel()
{
Product = new Product();
}
public ProductFormViewModel(Product product)
{
Product = product;
}
}
}

Answer 1

Do you need to edit the ID? if the ID is the PK of the product in your table then it could be a binding issue.
Try
[MetadataType(typeof(ProductMetaData))]
[Bind(Exclude="ID")]
public partial class Product
{
public Product()
{
// Initialize Product
this.CreateDate = System.DateTime.Now;
}
}

Answer 2

could you post your Model source code? does model have fields of class you want to update or just this class as object(Product)?
the problem could exists becouse when your model has object Product, you should pass to UpdateModel method prefix with name of the class...

Answer 3

The problem with UpdateModel(product, "Product"); is that you are using the same prefix (Product) as the Product class name. Try using a different prefix. For this you might need to rename the Product property of the ProductFormViewModel class.