C# 4 and .NET 4

MVC ❘ 1273
using System.ComponentModel.DataAnnotations;
namespace PCSMVCMagicShop.Models
{
public class ProductMetadata
{
[StringLength(20)]
public object Name { get; set; }
}
}
This will validate the data, as shown in
Figure 42-16.
Obviously the code you need to use in the
controller comes down to the model you are using,
and this option may not always be available, but it
can be very useful in the right circumstances.
code snippet PCSMVCMagicShop/Models/ProductMetadata.cs
You will also probably want to edit the view
figure 42-16
created to provide more meaningful text, but the
skeleton created is suitable for most needs. In this example, you’d probably want to change the form’s title
and validation messages, as well as providing a bit more space for the item description.
editing items with edit()
Editing items uses very similar code to creating new items. Rather than working through how to do this,
let’s just take a look at the code in the controller:
public ActionResult Edit(int id)
{
var productToEdit = (from p in entities.Products
where p.ProductId == id
select p).First();
}
return View(productToEdit);
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Edit(Product productToEdit)
{
try
{
var originalProduct = (from p in entities.Products
where p.ProductId == productToEdit.ProductId
select p).First();
}
if (!ModelState.IsValid)
{
return View(originalProduct);
}
entities.ApplyCurrentValues(originalProduct.EntityKey.EntitySetName,
productToEdit);
entities.SaveChanges();
return RedirectToAction("Index");
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