Good way to refresh databinding on all properties of a ViewModel when Model changes

Question

Short Version

If I update the Model object that my ViewModel wraps, what's a good way to fire property-change notifications for all the model's properties that my ViewModel exposes?

Detailed Version

I'm developing a WPF client following the MVVM pattern, and am attempting to handle incoming updates, from a service, to data being displayed in my Views. When the client receives an update, the update appears in the form of a DTO which I use as a Model.

If this model is an update to an existing model being shown in the View, I want the associated ViewModel to update its databound properties so that the View reflects the changes.

Let me illustrate with an example. Consider my Model:

class FooModel {   public int FooModelProperty { get; set; } } 

Wrapped in a ViewModel:

class FooViewModel {   private FooModel _model;    public FooModel Model    {      get { return _model; }     set      {        _model = value;        OnPropertyChanged("Model");      }   }    public int FooViewModelProperty   {     get { return Model.FooModelProperty; }     set      {       Model.FooModelProperty = value;       OnPropertyChanged("FooViewModelProperty");     }     } 

The Problem:

When an updated model arrives, I set the ViewModel's Model property, like so:

instanceOfFooVM.Model = newModel; 

This causes OnPropertyChanged("Model") to fire, but not OnPropertyChanged("FooViewModelProperty"), unless I call the latter explicitly from Model's setter. So a View bound to FooViewModelProperty won't update to display that property's new value when I change the Model.

Explicitly calling OnPropertyChanged for every exposed Model property is obviously not a desirable solution, and neither is taking the newModel and iterating through its properties to update the ViewModel's properties one-by-one.

What's a better approach to this problem of updating a whole model and needing to fire change notifications for all its exposed properties?

Answer 1

According to the docs:

The PropertyChanged event can indicate all properties on the object have changed by using either null or String.Empty as the property name in the PropertyChangedEventArgs.