protected override async void OnNavigatedTo(NavigationEventArgs e)
{
if (e.Parameter is not ComicRootPageNavigationArguments args)
{
throw new ProgrammerError("A ComicRootPage must receive a ComicRootPageNavigationArguments as its parameter.");
}
this._navigationTag = args.NavigationTag;
var savedState = ComicItemGridCache.GetRoot(args.NavigationTag);
// We only want to restore the scrollviewer position if the user navigates *back* to this page.
if (savedState is not null && e.NavigationMode is NavigationMode.New)
{
savedState.ScrollOffset = 0;
}
this.viewModel = ComicItemGridViewModel.ForTopLevelNavigationTag(this, args.MainViewModel, savedState);
this.ComicsCount = viewModel.TotalItemCount;
this.Initialized?.Invoke(this);
await this.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
this.InnerContentFrame.Navigate(typeof(ComicItemGrid), new ComicItemGridNavigationArguments {
ViewModel = viewModel,
OnNavigatedTo = (grid, _) => this.ComicItemGrid = grid
}));
}
protected override async void OnNavigatedTo(NavigationEventArgs e)
{
if (e.Parameter is not ComicNavigationItemPageNavigationArguments args)
{
throw new ProgrammerError("A ComicRootPage must receive a ComicNavigationItemPageNavigationArguments as its parameter.");
}
this._navigationTag = args.NavigationTag;
this._comicItem = args.ComicItem;
var savedState = e.NavigationMode switch {
NavigationMode.New => null,
NavigationMode.Back => ComicItemGridCache.PopStack(this.NavigationTag, this.ComicItem.Title),
_ => throw new ProgrammerError("Unexpected switch case"),
};
this.viewModel = ComicItemGridViewModel.ForSecondLevelNavigationTag(this, args.MainViewModel, args.ComicItem.Comics, args.Properties, savedState);
this.ComicsCount = viewModel.TotalItemCount;
this.Initialized?.Invoke(this);
await this.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
this.InnerContentFrame.Navigate(typeof(ComicItemGrid), new ComicItemGridNavigationArguments {
ViewModel = viewModel,
HighlightedComicItem = args.ComicItem,
OnNavigatedTo = (grid, e) => {
this.ComicItemGrid = grid;
grid.FinishNavigateInConnectedAnimationIfExists(this.ComicItem);
}
})
);
}
protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
{
// For now, we push useless information onto the cache to keep everything else working
if (e.NavigationMode is NavigationMode.New)
{
ComicItemGridCache.PushStack(this.NavigationTag, this.PageName, new ComicItemGridState(new(), 0, this.MainViewModel.LastModified));
}
// Ideally this should be automated
this.ViewModel.RemoveEventHandlers();
}
protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
{
if (this.ComicItemGrid is null)
{
throw new ProgrammerError("Navigating out of a ComicNavigationItemPage that wasn't initialized.");
}
ComicItemGridCache.PutRoot(this.NavigationTag, this.ComicItemGrid.GetSaveState());
// Ideally this should be automated
this.viewModel !.RemoveEventHandlers();
this.ComicItemGrid.DisposeAndInvalidate();
}
protected override async void OnNavigatedTo(NavigationEventArgs e)
{
if (e.Parameter is not ComicWorkItemPageNavigationArguments args)
{
throw new ProgrammerError("A ComicWorkItemPage must receive a ComicWorkItemPageNavigationArguments as its parameter.");
}
this._viewModel = args.ViewModel;
await this.ViewModel.InitializeAsync();
if (this.ViewModel.Initialized)
{
this.useThumbnails = this.ViewModel.ShouldUseThumbnails();
}
// After we change the visual state here, if the grid had already loaded, it may have initialized
// with a wrong value for useThumbnails. So we call it again.
// Note: Calling VisualStateManager.GoToState will set this.ComicSubitemGrid.ItemsPanelRoot to null (temporarily).
// For that purpose we must do this before setting visual state.
if (this.ComicSubitemGrid.IsLoaded)
{
this.RecalculateGridItemSize(this.ComicSubitemGrid);
}
if (this.ViewModel.Subitems.Count == 0)
{
_ = VisualStateManager.GoToState(this, "NoSubitems", false);
}
else
{
if (this.useThumbnails)
{
_ = VisualStateManager.GoToState(this, "ThumbnailsVisible", false);
}
else
{
_ = VisualStateManager.GoToState(this, "ThumbnailsHidden", false);
}
}
switch (e.NavigationMode)
{
case NavigationMode.New:
// Note: We may change the HighlightedComicItem's thumbnail size by setting visual manager state,
// so we should start the connected animation after.
this.HighlightedComicItem.TryStartConnectedAnimationToThumbnail(this.ViewModel.ComicItem);
break;
case NavigationMode.Back:
_ = ComicItemGridCache.PopStack(this.NavigationTag, this.PageName);
break;
default:
throw new ProgrammerError("Unexpected navigation mode");
}
this.ViewModel.ComicItem.PropertyChanged += this.ComicItem_PropertyChanged;
this.SynchronizeLovedStatusToUI();
if (await this.ViewModel.TryLoadDescriptionsAsync(this.InfoTextBlock))
{
this.ToggleInfoPaneButton.Visibility = Visibility.Visible;
}
if (this.ViewModel.Initialized && this.useThumbnails)
{
await this.ViewModel.LoadThumbnailsAsync();
}
}
