datareader with sqlhelper and run time label bind in grid

SqlConnection con = new SqlConnection(obj.conString);
        SqlCommand cmd = new SqlCommand();
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.CommandText = "SHOWDATA";
        cmd.Parameters.Add("@Root", SqlDbType.Int).Value = DropDownList2.SelectedValue;
        cmd.Connection = con;

        try
        {
            con.Open();
            GridView2.EmptyDataText = "No Records Found";
            GridView2.DataSource = cmd.ExecuteReader();
            GridView2.DataBind();


            foreach (GridViewRow row in GridView2.Rows)
            {
                string id = ((HiddenField)row.Cells[2].FindControl("hnfID")).Value.ToString();
                Label lbtsanstha = ((Label)row.Cells[2].FindControl("lblsanstah"));
                SqlDataReader rdr = SqlHelper.ExecuteReader(obj.conString, CommandType.Text, "select * from SansthUserDetail where userid='" + id + "'");
                while (rdr.Read())
                {
                    string col1Value = rdr["Sanstha"].ToString();                
                    lbtsanstha.Text = lbtsanstha.Text + ' ' + col1Value + ",".ToString();                
                }
                lbtsanstha.Text = lbtsanstha.Text.Substring(0, lbtsanstha.Text.Length - 1);
            }

        }
        catch (Exception ex)
        { throw ex; }

        finally
        { con.Close(); con.Dispose(); }