download button in a datalist control in asp.net

SqlCommand cmd = new SqlCommand("select * FROM WordFiles where id=@id ", con);
               cmd.Parameters.AddWithValue("id",DataList1.SelectedItem.ToString());

               SqlDataAdapter da = new SqlDataAdapter(cmd);
               DataTable dt = new DataTable();
               dt.TableName = "WordFiles";
               da.Fill(dt);
               DataSet dS = new DataSet();
               dS.DataSetName = "WordFiles";
               dS.Tables.Add(dt);
              // StringWriter sw = new StringWriter();
             //  dS.WriteXml(sw, XmlWriteMode.IgnoreSchema);
              // string s = sw.ToString();

               SqlDataReader drr = cmd.ExecuteReader();


               if (drr.Read())
               {
               // string attachment = "attachment; filename=test.xml";
               Response.ClearContent();
               Response.ContentType = drr["type"].ToString();
               Response.AddHeader("content-disposition", "attachment;filename=" + drr["name"].ToString());
               Response.BinaryWrite((byte[])drr["data"]);
               Response.End();