Dropdown box Data binding two ways

1, the use of CS package, DataAccess.cs

#region
String m_str = @ "Select Sname from service Group by sname";
DataTable M_dt = DataAccess.DBHelper.GetList (m_str);
Dropdownlist2.datavaluefield = "Sname";
Dropdownlist2.datatextfield = "Sname";
Binding data Source this
. Dropdownlist2.datasource = M_dt;
Dropdownlist2.databind ();

DropDownList2.Items.Insert (0, New ListItem ("Please select", ""));
#endregion

And in the web.config,

<appSettings>
    <!--database connection string-->
    <add key= "dbconnstring" value= "Data source=localhost; Database=manager;uid=sa;pwd=sa; "/>
  </appSettings>

2,

 SqlConnection conn = new SqlConnection ("Data Source = localhost; Database = Manager; Uid=sa;
        Pwd=sa; "); Conn.

        Open (); Task type binding #region SqlDataAdapter SDT = new SqlDataAdapter ("Select sname from service Group by Sname", conn)

        ;
        DataSet dt = new DataSet (); Sdt.
        Fill (DT);
        Dropdownlist2.datavaluefield = "Sname";
        Dropdownlist2.datatextfield = "Sname"; This.
        Dropdownlist2.datasource = DT;

        Dropdownlist2.databind ();
        DropDownList2.Items.Insert (0, New ListItem ("Please select", "")); #endregion Conn. Close ();