i want to create a dynamic drop down list from a method that takes, primary key, value and table name; But I am unable to populate the dropdown.

I am a learner in asp.net so explain in simple terms with examples

here is my code....

front end
Code Csharp:
  <asp:DropDownList id="UserPaidStatus" runat="server">

backend method call
Code Csharp:
 DropDownList UserPaidStatus = DataAutoPopulate.MakeNewDDL("cn_UserPaidStatus", "m_paidstatus", "m_id");

my method that is called
Code Csharp:
public static DropDownList MakeNewDDL(string tableName, string columnName, string primaryKeyColumn)
        DropDownList ddl = new DropDownList();
        // create connection to database
        SqlConnection con = netCmsConnection.getDatabaseConnection();
        String query = ("SELECT " + columnName + ", " + primaryKeyColumn + " FROM " + tableName);
        SqlCommand command = new SqlCommand(query, con);
        command.CommandType = CommandType.Text;
        SqlDataAdapter adaptor = new SqlDataAdapter(command);
        DataTable dt = new DataTable();
        return ddl;

any ideas what i am doing wrong?