public RegistrationView(RegistrationViewModel registrationViewModel)
{
InitializeComponent();
_viewModel = registrationViewModel ??
throw new ArgumentNullException(nameof(registrationViewModel));
SetBindings();
_buttonSavePatient.Click += (s, e) => _viewModel.SavePatient();
_buttonAddObserv.Click += ButtonAddObserv_Click;
_buttonAddDoctor.Click += ButtonAddExam_Click;
_buttonAddHospital.Click += ButtonAddHospital_Click;
}