private void deleteAppointmentButton_Click(object sender, EventArgs e)
        {
            var selectedAppointment = GetItemFromSelectedRow(appointmentGridView);

            if (selectedAppointment == null)
            {
                return;
            }
            var id = selectedAppointment.Id;

            appointmentService.Delete(id);
            reminderService.DeleteByAppointmentId(id);
            List <AppointmentAggregate> newAppointmentList = appointments.ToList();

            newAppointmentList.Remove(appointments.First(p => p.Id == id));
            initBindingSource(newAppointmentList);
            appointmentBindingSource.ResetBindings(false);
        }