private void gearComboBox_SelectedIndexChanged(object sender, EventArgs e) { if (gearComboBox.SelectedIndex == -1) { LoadAd(); } else { try { DgwIlan.DataSource = _adService.GetAdByCarsId( _carsService.GetCarsByGear(Convert.ToInt32(gearComboBox.SelectedValue))); } catch (Exception ex) { Console.WriteLine(ex); throw; } } }