c# - MVVM - How to use a given REST-API dll -

i'm starting learn mvvm in c# mvvmlight. other project, have given (but self-made) rest-api dll. dll i'm trying use in new project. completly based on api. i'm unsure "model"-part , don't want repeat myself while coding.

problem this: application has several "plugins/sections". let's @ sample "groups" section. api defines groups-entity-class properties "groupname, permissions, members". then, application must have groups model , groupsviewmodel , groupsview ui. there, must list/show "groupname, permissions, members".

question is: have redeclare properties dll-entity-class in mvvm-model-class? or best way use rest api? there pattern. read extension object pattern. have no clue.

hint: since api written myself (only classes, no mvvm or other frameworks), modify needed.

thanks in advance!

take @ repository pattern: https://msdn.microsoft.com/en-us/library/ff649690.aspx. basically create repository api calls, , transforms entities format can use in view.

if the objects api sufficient can return them, otherwise convert them in repository more useful.

in viewmodel ask repository return the model, , need not care how and in format got them.

small example:

interface iapirepository {     task<observablecollection<apimodel>> getapimodelsasync(); }  class apirepository : iapirepository {     private async task<observablecollection> getapimodelsasync()     {         var mycollection = new observablecollection<apimodel>();         var result = await domyapicall();         foreach (result item)         {             var newmodel = new apimodel();             newmodel.fillfromapi(item);             mycollection.add(newmodel);         }         return mycollection;     }    }   class myviewmodel : viewmodelbase {     private readonly iapirepository _apirepository;      public myviewmodel(iapirepository apirepository)     {         _apirepository = apirepository;         initializeviewmodel();     }      private observablecollection<apimodel> _apimodels;     public observablecollection<apimodel> apimodels     {         { return _apimodels; }         set { set(ref _apimodels, value); }     }      private async void initializeviewmodel()     {         //as repo finished apimodels raise raisepropertychanged event         apimodels = await _apirepository.getapimodelsasync();     } }  //in viewmodellocator simpleioc.default.register<iapirepository, apirepository>(); simpleioc.default.register<myviewmodel>();  //construct viewmodel (with injected repository) var vm = simpleioc.default.getinstance<myviewmodel>(); 

with of pattern can do other awesome things: 

• if add new data source need change repository , not viewmodel.
• if want test view (for example in design mode) can inject a mockapirepository which returns sample data instead of doing api call