private void EditPatient()
        {
            var window      = new PatientAddEditView();
            var dataContext = new PatientAddEditViewModel(SelectedPatient);

            window.DataContext = dataContext;
            if (window.ShowDialog() == true)
            {
                SelectedPatient.OnPropertyChanged();
            }
        }
        private void AddPatient()
        {
            var window      = new PatientAddEditView();
            var dataContext = new PatientAddEditViewModel();

            window.DataContext = dataContext;
            if (window.ShowDialog() == true && dataContext.Model != null)
            {
                Patients.Add(dataContext.Model);
            }
        }