public override void LoadData() { NavigationHelper.IsBusy = true; BackgroundProcessFactory.RunAsync(null, (o, e) => { e.Result = DBDataSource.GeTestAttempts(); }, (o, e) => { NavigationHelper.IsBusy = false; if (e.Error != null) { return; } else { var attemts = e.Result as List <TestAttempt>; if (attemts != null) { ResultList = new ObservableCollection <TestAttempt>(attemts); _cv = CollectionViewSource.GetDefaultView(ResultList); _cv.Filter = FilterValid; _cv.Refresh(); } } }); }