title: MVVM - How to use a given REST-API dll
body: <p>I'm starting to learn MVVM in C# with mvvmlight. From an other project, I have a given (but self-made) REST-API as a dll. This dll I'm trying to use in this new project. It is completly based on this API. I'm unsure about the "model"-part and don't want to repeat myself while coding. </p>
  
  <p><strong>Problem is like this</strong>: The application has several "plugins/sections". Let's look at a sample like the "groups" section. Now the API defines a groups-Entity-Class with all properties like "groupname, permissions, members". Then, the Application must have a groups model and also a groupsViewModel and a GroupsView for the UI. There, I also must list/show "groupname, permissions, members". </p>
  
  <p><strong>Question is:</strong> Do I have to redeclare all the properties from the dll-entity-class in the mvvm-model-class? Or what is the best way to use a rest api? Is there any pattern. I read about the Extension Object Pattern. But I have no clue.</p>
  
  <p>Hint: Since the API is written by myself (only classes, no mvvm or other frameworks), I could modify it as needed.</p>
  
  <p>Thanks in advance!</p>