public void GoToAppointmentView(object sender, RoutedEventArgs e)
        {
            var         button          = sender as Button;
            Appointment appointment     = (Appointment)button.Tag;
            var         AppointmentView = new AppointmentWindow(appointment);

            AppointmentView.Show();
        }
        public void GoToAppointmentsView(object sender, RoutedEventArgs e)
        {
            var button = sender as Button;
            List <Appointment> appointments = (List <Appointment>)button.Tag;

            foreach (Appointment appointment in appointments)
            {
                var AppointmentView = new AppointmentWindow(appointment);
                AppointmentView.Show();
            }
        }