// Update joke in list
private void OnJokeUpdated(JokeDetailViewModel viewModel, Joke joke)
{
var updatedJoke = Jokes.Single(j => j.Id == joke.Id);
updatedJoke.Text = joke.Text;
}
// Add new joke to list
private void OnJokeAdded(JokeDetailViewModel viewModel, Joke joke)
{
Jokes.Add(new JokeViewModel(joke));
SortJokesDesc();
}