private void button4_Click(object sender, EventArgs e) { string station = (string)stationsList.SelectedItem; string city = (string)citiesList.SelectedItem; Station selectedStation = findSelectedStation(station); Stopwatch stopwatch = Stopwatch.StartNew(); string informations = client.GetInformations(selectedStation.Number, city); stopwatch.Stop(); label8.Text = "Execution time of GetInformations: " + stopwatch.ElapsedMilliseconds + "ms"; label8.Visible = true; label7.Text = informations; }