/// <summary>
 /// Standard WP7 method which is running always when user presses back key.
 /// </summary>
 /// <param name="e">NavigationService argument</param>
 protected override void OnBackKeyPress(CancelEventArgs e)
 {
     if (_viewModel.DownloadListStatus.ProgressBar.IsEnabled)
     {
         _viewModel.Operations.Abort();
         e.Cancel = true;
     }
     if (_downloader != null)
     {
         _downloader.Abort();
         _viewModel.DownloadSurveysStatus.IsCanceled = true;
         e.Cancel = true;
         _downloader = null;
     }
     else if (!_viewModel.DownloadSurveysStatus.CanCancel)
     {
         MessageBox.Show(Languages.AppResources.listOfNewSurveysPage_TooLateInterrupt);
         return;
     }
     base.OnBackKeyPress(e);
 }
 private void OnDownloadSurveys(object sender, EventArgs e)
 {
     if (_viewModel.DownloadSurveysStatus.ProgressBar.IsEnabled || _viewModel.DownloadListStatus.ProgressBar.IsEnabled)
     {
         MessageBox.Show(Languages.AppResources.listOfNewSurveysPage_DownloadingProgress);
         return;
     }
     //else if (_viewModel.List.Count == 0)
     //{
     //    MessageBox.Show(Languages.AppResources.listOfNewSurveysPage_NothingDownload);
     //    return;
     //}
     BusyIndicator.DataContext = _viewModel.DownloadSurveysStatus.ProgressBar;
     _downloader = new DownloadNewSurveys(_viewModel.Operations, new List<SurveyBasicInfo>(_viewModel.List), _viewModel.DownloadSurveysStatus);
     _downloader.Download();
     //_viewModel.List.Clear();
 }