private void BAdd_Click(object sender, RoutedEventArgs e)
 {
     try
     {
         if ((string)((TabItem)PlayListTabs.SelectedItem).Header == "Найденые...")
         {
             var listBox = (ListBox)PlayListTabs.SelectedContent;
             var audio   = (Audio)listBox.SelectedItem;
             VkApi.AddAudio(audio.OwnerID, audio.ID);
             foreach (TabItem tabItem in PlayListTabs.Items)
             {
                 if ((string)tabItem.Header == "My music")
                 {
                     var listBox2 = (ListBox)(tabItem).FindName("PlayListBox");
                     if (listBox2 != null)
                     {
                         listBox2.Items.Insert(0, audio);
                     }
                 }
             }
         }
     }
     catch (NetworkInformationException)
     {
         System.Windows.Forms.MessageBox.Show(@"Ошибка интернет соединения.");
     }
 }