StandaloneNode.DBConnection.MySqlConnect C# (CSharp) Méthode

        public string MySqlConnect()
        {
            string dbHost = connectionInfo.ElementAt<string>(0);
            string dbUser = connectionInfo.ElementAt<string>(1);
            string dbPass = connectionInfo.ElementAt<string>(2);
            string dbName = connectionInfo.ElementAt<string>(3);
            //Console.WriteLine(dbHost + "-" + dbUser);
            // 如果有特殊的編碼在database後面請加上;CharSet=編碼, utf8請使用utf8_general_ci 
            string connStr = "server=" + dbHost + ";uid=" + dbUser + ";pwd=" + dbPass + ";database=" + dbName;// +";CharSet=utf8_general_ci"; ;// ";CharSet=utf8mb4;";
            conn = new MySqlConnection(connStr);

            // 連線到資料庫 
            try
            {
                conn.Open();
                return "";
            }
            catch (MySql.Data.MySqlClient.MySqlException ex)
            {
                conn = null;
                switch (ex.Number)
                {
                    case 0:
                        return "無法連線。";
                    case 1045:
                        return "使用者帳號或密碼錯誤，請再試一次。";
                    case 1049:
                        return dbName + "不存在，請再試一次。";
                    default:
                        return "發生不明連線錯誤。";
                }
            }
        }
        public MySqlDataReader mysql_query(string sql)

 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();
 }