C#

private async void btnSFilter_Click(object sender, RoutedEventArgs e)
        {
            if (txtSDate1.Date > txtSDate2.Date)
            {
                var messageDialog = new MessageDialog("Invalid period of time, please try again later.");
                await messageDialog.ShowAsync();
                return;
            }

            BloodResultsDAO brdao = new BloodResultsDAO();
            List<BloodResults> result = await brdao.GetData(DateTime.Parse(txtSDate1.Date.ToString()), DateTime.Parse(txtSDate2.Date.ToString()), true);
            ObservableCollection<Data> dresult = new ObservableCollection<Data>();

            foreach (BloodResults br in result)
            {
                DateTime date = DateTime.Parse(br.registered);
                string dateR = date.Month.ToString() + "/" + date.Day.ToString();
                dresult.Add(new Data() { Category = dateR, Value = br.result, Info = "Result of " + dateR + ", " + br.result });
            }

            telChart.Series[0].ItemsSource = dresult;
        }