public MapViewModel(INavigationResolver resolver, DataService.IGeoDataService service) 
 {
     _resolver = resolver;
     _service = service;
     Issues = new ObservableCollection<DataService.IssueItem>();
     InitData();
 }
 public AddViewModel(INavigationResolver navigationResolver, DataService.IGeoDataService service)
 {
     _resolver = navigationResolver;
     _service = service;
 }