private void button2_Click(object sender, EventArgs e) { stationsList.Items.Clear(); selectedStations.Clear(); Stopwatch stopwatch = Stopwatch.StartNew(); Station[] stations = client.GetStationsOf((string)citiesList.SelectedItem); stopwatch.Stop(); int s = stations.Length; for (int i = 0; i < s; i++) { stationsList.Items.Add(stations[i].Name); selectedStations.Add(stations[i]); } selectNewStationButton.Enabled = false; label4.Text = "Execution time of GetStationsOf: " + stopwatch.ElapsedMilliseconds + "ms"; label4.Visible = true; button2.Enabled = false; stationsList.Enabled = true; }