private void cb_code_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (cb_code.Text.Trim()!=string.Empty)
            {
            string sql = "select * from STATION";
            string Where = "where CODE like '%"+cb_code.Text.Trim()+"%'";
            MessageBox.Show(sql + Where);
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                OracleCommand command = new OracleCommand(sql+Where, connection);
                connection.Open();
                using (OracleDataReader reader = command.ExecuteReader())
                {
                    // Always call Read before accessing data.
                    int i = 0;
                    while (reader.Read())
                    {
                        cb_code.Items.Add(reader.GetString(i));
                        
                    }
                }
            }
            


            }
        }