private async void OnBrewerySelectedCommandExecuted(DatumB brewer)
{
NavigationParameters navParams = new NavigationParameters();
navParams.Add("brewer", brewer);
await _navigationService.NavigateAsync("BreweryDetailPage", navParams);
}
public void OnNavigatingTo(NavigationParameters parameters)
{
Model = parameters.GetValue <DatumB>("brewer");
}