public ReportWindow()
        {
            InitializeComponent();

            dpFromDate.SelectedDate = dpToDate.SelectedDate = DateTime.Now;

            DataContext = new DrawColumnChart(dpFromDate, dpToDate);
        }
 private void BtnColumnChart_Click(object sender, RoutedEventArgs e)
 {
     DataContext = new DrawColumnChart(dpFromDate, dpToDate);
 }