public Form1() { InitializeComponent(); dataBase = new ParsedDataCollection(); dataCollectionBindingSource.DataSource = dataBase; dataGridView1.DataSource = dataCollectionBindingSource; OrdersDAL sqlbase = new OrdersDAL(); sqlbase.OpenConnection(ConfigurationManager.ConnectionStrings[ "Vmax44Parser.Properties.Settings.vmax44parserConnectionString"].ToString()); DataTable orders = sqlbase.GetAllOrdersAsDataTable(); foreach (DataRow row in orders.Rows) { comboBox1.Items.Add(row.Field <string>("OrderNumber")); } sqlbase.CloseConnection(); }