title: Calling WCF services in MVVM?
body: <p>I am working on a Prism desktop application and would like to know the best way to deal with lookup / reference data lists when using a WCF backend. I think this question may cover a few areas and I would appreciate some guidance </p>
  
  <p>For example, consider a lookup that contains Products(codes and descriptions) which would be used in a lot of different input screens in the system.</p>
  
  <ol>
  <li>Does the viewmodel call the WCF service directly to obtain the data to fill the control?</li>
  <li>Would you create a control that solely deals with Products with its own viewmodel etc and then use that in every place that needs a product lookup or would you re-implements say a combobox that repopulates the products ItemsSource in every single form view model that uses it?</li>
  <li>Would I create a brand new WCF service called something like LookupData service and use that to populate my lookup lists? - <em>I am concerned I will end up with lots of lookups if I do this.</em></li>
  <li>What other approaches are there for going about this?</li>
  </ol>