public async void RefreshAllBooks()
{
var b = await _bookDomain.GetAllAsync();
AllBooks = b != null ? new ObservableCollection <Book>(b) : new ObservableCollection <Book>();
Books = CollectionViewSource.GetDefaultView(AllBooks);
Books.CollectionChanged += Books_CollectionChanged;
SourceDirectories.Clear();
SourceDirectories =
new ObservableCollection <SourceDirectory>(_sourceDomain.GetAllSourceDirectories().ToList());
SourceDirectories.Insert(0,
new SourceDirectory {
SourceDirectoryUrl = "All Sources", NickName = "All Sources"
});
SourceDirectoryFilter = SourceDirectories[0];
}
