title: CQRS, Wpf + UI Refresh
body: <p>my company is creating a new software for product selling. We decide to use the DDD+CQRS infrastructure and WPF for the presentation layer, but I don't know how my UI will be notified when an event is raised.
  1) Question:
  - The Operator click "Register" button to save an Order. 
  - My ViewModel send a RegisterOrderCommand to the Command Bus
  - A "RegisterOrderCommandHandler" manages the command
  - An OrderAggregateRoot in the Domain Layer registers the order.
  - A Domain Event "RegisterOrderEvent" is sent to the Event Bus.</p>
  
  <p>How I can notify my UI that the operation is completed?
  Is it correct that my ViewModel registers an EventHandler to manage an event in the Domain Layer?</p>
  
  <p>2) Question:
  Is similar to the first one. I've an external device that want to communicate with me. Where I've to place the listener? In the domain layer, in the application layer or in the infrastructure layer?</p>
  
  <p>Thanks</p>