private void Upload_List(object sender, RoutedEventArgs e)
 {
     currentListName = ShowModalWindow("ВВедіть назву списку");
     if (currentListName == string.Empty)
     {
         return;
     }
     todoList             = TaskController.DownloadList(currentListName);
     listView.ItemsSource = todoList;
     tbListName.Text      = currentListName;
 }