private void btnSubmit_Click(object sender, RoutedEventArgs e)
        {
            if (txtNameVis.Text == "" || datepick.SelectedDate.Equals(null) || txtEmail.Text == "" || txtPhone.Text == "")
            {
                MessageBox.Show("Invalid input!");
                return;
            }

            DateTime dob = (DateTime)datepick.SelectedDate;

            VisitorController.getInstance().add(txtNameVis.Text, dob, txtEmail.Text, txtPhone.Text);
            MessageBox.Show("Success add new visitor!");
            reset();
            load();
        }
        private void btnRemove_Click(object sender, RoutedEventArgs e)
        {
            MessageBoxResult messageBoxResult = System.Windows.MessageBox.Show("Are you sure?", "Delete Confirmation", System.Windows.MessageBoxButton.YesNo);

            object id_obj = ((Button)sender).CommandParameter;
            int    id;

            int.TryParse(id_obj.ToString(), out id);

            if (messageBoxResult == MessageBoxResult.Yes)
            {
                VisitorController.getInstance().remove(id);
                MessageBox.Show("Success remove visitor data!");
            }
            load();
        }
        private dynamic getVisitorList()
        {
            List <Visitor> visitors = VisitorController.getInstance().getAll();

            var visitors_stats = visitors.Where(v => v.Status == "Active");

            var visitors_filterd = visitors_stats.Select(v => new
            {
                v.Id,
                v.Name,
                v.DOB,
                v.Email,
                v.phoneNumber
            });

            return(visitors_filterd);
        }
        private void btnUpdate_Click(object sender, RoutedEventArgs e)
        {
            object id_obj = ((Button)sender).CommandParameter;
            int    id;

            int.TryParse(id_obj.ToString(), out id);

            if (txtNameVis.Text == "" || datepick.SelectedDate.Equals(null) || txtEmail.Text == "" || txtPhone.Text == "")
            {
                MessageBox.Show("Invalid input!");
                return;
            }

            DateTime dob = (DateTime)datepick.SelectedDate;

            VisitorController.getInstance().update(id, txtNameVis.Text, dob, txtEmail.Text, txtPhone.Text);
            MessageBox.Show("Success update visitor data!");
            reset();
            load();
        }