Blank crystal report using typed dataset visual c# 2008

I am fairly new to c# and am having trouble displaying my selected database data which will have been loaded into a datatable of a typed dataset in a crystal report. The report comes out blank each time even after selecting the option in crystal reports to display the selected datatable column.Can someone please assist. The code i hve used is below, maybe there is something wrong with the code but i just cant crack it.

private void getReportDataSelection()

        {

          

            DataSet Ds = new DataSet();

            

            

if (radiobutton1.Checked  )

            {

                

ArrayList aList = new ArrayList();

                

string cString = "Data Source=Server\\SQLEXPRESS;InitialCatalog=MyDb;Integrated Security=True";

               

 SqlConnection myConnection = new SqlConnection(cString);

                

CrystalReport9  report = new CrystalReport9 ();

                               

                myConnection.Open();

                

String Query1 = ("SELECT sum(column1)FROM Table1");

                

SqlDataAdapter ad = new SqlDataAdapter(Query1, myConnection);

 

 //my_dt is the name of the datatable in the typed dataset              

ad.Fill(Ds  , "my_dt");

                if (Ds.Tables[0].Rows.Count != 0)

                {

                

  report.SetDataSource(Ds.Tables[0]);

                    

rptViewer.crystalReportViewer1.ReportSource = report;

                }

                                 

                         

                myConnection.Close();

 

            }

Thanks in advance,