StandaloneNode.DBConnection.mysql_query C# (CSharp) Méthode

        public MySqlDataReader mysql_query(string sql)
        {
            try
            {
                MySqlCommand cmd = new MySqlCommand(sql, conn);
                cmd.CommandTimeout = 120000;
                MySqlDataReader myData = cmd.ExecuteReader();
                return myData;
            }
            catch (Exception ex)
            {
                //mydata.AppendText( sql + "\r\nError " + ex.Number + " : " + ex.Message);
                Console.WriteLine("錯啦  " + ex.ToString());
            }
            return null;
        }
        public void closeMySqlConnection()

 public SearchForm(List<string> dbInfo)
 {
     InitializeComponent();
     this.dbInfo = dbInfo;
     postSort = new bool[levelOneList.Columns.Count];
     string sql = "select id, name from pages_info";
     DBConnection conn = new DBConnection(this.dbInfo);
     conn.MySqlConnect();
     MySqlDataReader res = conn.mysql_query(sql);
     while (res.Read())
     {
         pagesID.Add(res.GetString(0));
         pagesName.Add(res.GetString(1));
         page_list.Items.Add(res.GetString(1));
     }
     page_list.Text = page_list.Items[0].ToString();
     page_list.SelectedIndex = 0;
     res.Close();
 }