Question

I’m facing some design questions in my wpf MVVM (Prism based) application, would be happy to get your advice.
My model is very simple:

public class Customer
{
   public string FirstName {get;set;}
   public string LastName {get;set;}
}

As you can see, I don’t have any INotifyPropertyChnaged support for my Model class.
I also have ViewModel for the CustomerDetails screen, that support INotifyPropertyChanged.

public class CustomerDetailsViewModel:INotifyPropertyChanged /*Or NotificationObject*/
{
   /*INotifyPropertyChanged event */
   private Customer item;
   public Customer Item
   {
      get{return item;}
      set
      {
         item=value; 
         //Raise PropertyChanged
         //Set IsDirty to true
      }
   }
}

In my view, i’m using binding to the Item.FirstName and my ViewModel being updated.
My problem is – since only the FirstName property is being updated via the View, and the Model itself does not support INotifyPropertyChanged, hence the Item setter not being called, and the IsDirty remains equal to false (and therefore does not update the IsDirty notification on the UI).

I know I can support INotifyPropertyChanged in the model, and then register to the Item.PropertyChanged event in the view model, and actually set the IsDirty to true, But –
Since I’m also using CodeFirst, and my Model class shared between my ServerSide and my client side (Not using Add Service Reference), I don’t want to add the INotifyPreoprtyChanged stuff to my server side.

I’m considaring creating new project, that will use T4 templates to copy one by one all my Entities (as Customer) and adding INotifyPropertyChanged support to each and every model.
Is that something that seems reasonable or not? any other suggestions?

Thanks!

Answer 1

Option1.
Separate entities, which being transferred between client and server (DTO), from entities, which are models on the client side. Implement INPC in models. Use mapping between these entities.

Option2.
Bind view to view model properties only. Make view model properties, which wrap corresponding model properties.

Option 3.
Is a mix of first two options. Do not aggregate model in view model. Use mapping between model and view model. Make view model properties, which correspond to model properties.