private void BDelete_Click(object sender, RoutedEventArgs e)
 {
     try
     {
         var listBox = (ListBox)((TabItem)PlayListTabs.SelectedItem).FindName("PlayListBox");
         if (listBox != null)
         {
             var audio = (Audio)listBox.SelectedItem;
             VkApi.DeleteAudio(audio.OwnerID, audio.ID);
             listBox.Items.Remove(listBox.SelectedItem);
         }
     }
     catch (NetworkInformationException)
     {
         System.Windows.Forms.MessageBox.Show(@"Ошибка интернет соединения.");
     }
 }