public BookViewModel(int bookId)
{
bookModel = new BookModel();
isLoading = true;
currentHtmlContentFile = null;
previousHtmlContentFile = null;
nextHtmlContentFile = null;
currentAnchor = null;
navigateCommand = null;
previousCommand = null;
nextCommand = null;
bookModel.OpenBookAsync(bookId).ContinueWith(epubBook => BookOpened(epubBook), TaskScheduler.FromCurrentSynchronizationContext());
}
private void BookOpened(Task <EpubBook> task)
{
EpubBook epubBook = task.Result;
Navigation = new ObservableCollection <NavigationItemViewModel>(bookModel.GetNavigation(epubBook));
ReadingOrder = new ObservableCollection <HtmlContentFileViewModel>(bookModel.GetReadingOrder(epubBook));
if (ReadingOrder.Any())
{
CurrentHtmlContentFile = ReadingOrder.First();
if (ReadingOrder.Count > 1)
{
nextHtmlContentFile = ReadingOrder[1];
}
}
IsLoading = false;
NotifyPropertyChanged(nameof(IsPreviousButtonVisible));
NotifyPropertyChanged(nameof(IsNextButtonVisible));
}
private void Navigate(HtmlContentFileViewModel targetHtmlContentFileViewModel)
{
if (targetHtmlContentFileViewModel == null)
{
CurrentHtmlContentFile = null;
previousHtmlContentFile = null;
nextHtmlContentFile = null;
}
else if (CurrentHtmlContentFile != targetHtmlContentFileViewModel)
{
CurrentHtmlContentFile = targetHtmlContentFileViewModel;
int currentReadingOrderItemIndex = ReadingOrder.IndexOf(CurrentHtmlContentFile);
if (currentReadingOrderItemIndex != -1)
{
if (currentReadingOrderItemIndex > 0)
{
previousHtmlContentFile = ReadingOrder[currentReadingOrderItemIndex - 1];
}
else
{
previousHtmlContentFile = null;
}
if (currentReadingOrderItemIndex < ReadingOrder.Count - 1)
{
nextHtmlContentFile = ReadingOrder[currentReadingOrderItemIndex + 1];
}
else
{
nextHtmlContentFile = null;
}
}
else
{
previousHtmlContentFile = null;
nextHtmlContentFile = null;
}
}
NotifyPropertyChanged(nameof(IsPreviousButtonVisible));
NotifyPropertyChanged(nameof(IsNextButtonVisible));
}
