private void AddAnimalToZoo_Clicked(object sender, RoutedEventArgs e)
 {
     if (listBoxZoo.SelectedItem != null && listBoxAllAnimals.SelectedItem != null)
     {
         try
         {
             DbConnectionManager.AddAnimalToZoo(listBoxZoo, listBoxAllAnimals);
         }
         catch (Exception ex)
         {
             MessageBox.Show(ex.ToString());
         }
         finally
         {
             ShowAnimalsList();
         }
     }
     else
     {
         MessageBox.Show("Please select a zoo and animal first");
     }
 }