async void OnDismiss(object sender, EventArgs e)
{
Button button = (Button)sender;
button.IsEnabled = false;
this.IsBusy = true;
try
{
string title = titleCell.Text;
string author = authorCell.Text;
string genre = genreCell.Text;
if (string.IsNullOrWhiteSpace(title) ||
string.IsNullOrWhiteSpace(author) ||
string.IsNullOrWhiteSpace(genre))
{
this.IsBusy = false;
await this.DisplayAlert("Missing Information",
"You must enter values for the Title, Author, and Genre.",
"OK");
}
else
{
if (existingBook != null)
{
existingBook.Title = title;
existingBook.Genre = genre;
existingBook.Authors[0] = author;
await manager.UpdateAsync(existingBook);
int pos = books.IndexOf(existingBook);
books.RemoveAt(pos);
books.Insert(pos, existingBook);
}
else
{
Book book = await manager.AddAsync(title, author, genre);
books.Add(book);
}
await Navigation.PopModalAsync();
}
}
finally
{
this.IsBusy = false;
button.IsEnabled = true;
}
}