Best model for WPF+MVVM+EF 6.1 - wpf

Question

I’m trying to figure out best model for my WPF+MVVM+EF 6.1 application and I’m little confuse how to do this right after watching many EF courses and blogs. When modeling application in WPF there is a need for INotifyPropertyChanged, Observablecollection and also adding some additional calculated properties (not persisted on the database). I’m considering this solutions:
Change EF T4 template and implement INotifyPropertyChanged, change collections to Observablecollection and add additional fields in partial class. This brings to bind to EF model but looks simple and easer to maintain;
Use separate class for domain objects and rewrite data between them – for instance using automapper. This have separation of concerns but all updated and inserted entities have to be translated to appropriate EF entities.
Implement new class that have EF class nested inside new class with all properties wrapped and change tracked – this in other hand brings redundant code.
What will be best solution for this which not involve writing redundant code?

Answer 1

How about using the generated EF entities as it is and creating a DTO model that implements INotifyPropertyChanged only when it is necessary.
Not in every case you need to be able to synchronize the data between the view and the model right away.
Don't abuse the usage of INotifyPropertyChanged. It will be too late when you realize that you have a lot of extra code that doesn't actually need two way binding, a lot of repetitive work and can't be reused by other client view (could be an asp.net) because it's too technology specific (for example dependency property).
And the MVVM pattern works fine for a simple data display without you have to implement INotifyPropertyChanged for the binding data.
public class Order
{
public string OrderNo { get; set; }
public DateTime Date { get; set; }
}
public class WindowViewModel
{
public WindowViewModel()
{
var orders = Service<TheEntity>.Get();
Array.ForEach(orders, order => Orders.Add(order));
}
private readonly ObservableCollection<Order> _orders = new ObservableCollection<Order>();
public ObservableCollection<Order> Orders
{
get { return _orders; }
}
}
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new WindowViewModel();
}
}
<Window DataContext="{Binding RelativeSource={RelativeSource Self}}">
<ListView ItemsSource="{Binding Orders}">
<ListView.View>
<GridView>
<GridViewColumn Header="OrderNo" DisplayMemberBinding="{Binding OrderNo}"/>
<GridViewColumn Header="Date" DisplayMemberBinding="{Binding Date}"/>
</GridView>
</ListView.View>
</ListView>
</Window>

Answer 2

The best way is not to disturb auto-generated code from EF, even if you wrap it inside, new class, you still need some mechanism to track and save changes, doing it so completely overrides for what entity framework is designed for (less coding in DAL). The best way is to have properties (observable collection or i notify properties in VM- View Model). You might need to put little more code into your application but that helps you and to maintain the code and it will be total decoupled from other modules (BL, DAL, ..) of the application.