private void simpleButton2_Click(object sender, EventArgs e) { BusinessClass.ConfigDB(2); txtDB2.Text = BusinessClass.SecondConn.GetConnectionString(); List <string> tableNames = BusinessClass.SecondTables; cboTable2.Properties.Items.AddRange(tableNames); if (cboTable2.Properties.Items.Count > 0) { cboTable2.SelectedIndex = 0; } }