LINQ - Detaching DataContext

I took the code from here by Michael Petito and modified it so I could just use an extension class instead of having to change the model. Besides, it is more fun to use the new features of .NET 3.5 :)

using System.Data.Linq;
using System.Data.Linq.Mapping;

public static class ExtendedDataContext
{
public static T Detach(this DataContext dc, T entity) where T : class, new()
{
   if (entity == null)
       return null;

   //create a copy of the entity
   object entityCopy = new T();

   //enumerate the data member mappings for the entity type
   foreach (MetaDataMember member in dc.Mapping.GetMetaType(typeof(T)).DataMembers)
   {
       //skip associations and deferred members
       if (member.IsAssociation || member.IsDeferred)
           continue;

       //copy the member value
       member.StorageAccessor.SetBoxedValue(ref entityCopy, member.StorageAccessor.GetBoxedValue(entity));
   }

   return (T)entityCopy;
}
}

---

Code in use

User detachedUser = ((DataContext)db).Detach(user);
db.Users.Attach(detachedUser, true);
db.SubmitChanges();