private void DeleteZoo_Clicked(object sender, RoutedEventArgs e)
        {
            if (listBoxZoo.SelectedItem != null)
            {
                try
                {
                    DbConnectionManager.DeleteZoo(listBoxZoo);
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.ToString());
                }
                finally
                {
                    ShowZooList();

                    textZoo.Text = "";
                }
            }
            else
            {
                MessageBox.Show("Please select a zoo to delete");
            }
        }