private void tabControl1_SelectedIndexChanged(object sender, EventArgs e) { List <string> dt = service.GetAvailableCompanyNames(); List <string> locDt = service.GetAvailableLocNames(); for (int i = 0; i <= dt.Count - 1; i++) { namesCollection.Add(dt[i].ToString()); } companyBX.AutoCompleteMode = AutoCompleteMode.Suggest; companyBX.AutoCompleteSource = AutoCompleteSource.CustomSource; companyBX.AutoCompleteCustomSource = namesCollection; for (int i = 0; i <= locDt.Count - 1; i++) { locCollection.Add(locDt[i].ToString()); } locationBX.AutoCompleteMode = AutoCompleteMode.Suggest; locationBX.AutoCompleteSource = AutoCompleteSource.CustomSource; locationBX.AutoCompleteCustomSource = locCollection; }