public MainPageViewModel()
{
HasFiles = true;
AddDocumentCommand = new DelegateCommand(NavigateAddDocument);
AddImageCommand = new DelegateCommand(NavigateAddImage);
DeleteFileCommand = new DelegateCommand <StorageDocumentContainer>(DeleteFile);
FetchFilesCommand = new DelegateCommand(FetchStorageFiles);
Files = new ObservableCollection <StorageDocumentContainer>();
_modelUpdateToken = EventMessenger.GetEvent <ModelUpdatedMessageEvent <StorageDocument> >().Subscribe(OnModelUpdated);
FetchStorageFiles();
}