/// <summary>
/// Command callback.
/// Navigates back in the navigation history.
/// </summary>
private void OnNavigateBack()
{
try
{
KanjiNavigationEntry entry = _navigationHistory.Pop();
RaisePropertyChanged("CanNavigateBack");
// Apply the filter.
_kanjiFilter = entry.KanjiFilter;
KanjiFilterVm.SetFilter(_kanjiFilter);
if (_kanjiDetailsVm != null)
{
KanjiListVm.Navigate(_kanjiFilter,
_kanjiDetailsVm.KanjiEntity.DbKanji);
}
else
{
KanjiListVm.SetFilter(_kanjiFilter);
}
// Reset the kanji details viewmodel.
SetKanjiDetailsVm(entry.KanjiDetailsVm);
}
catch (InvalidOperationException)
{
// The command was fired several times in a
// row and the navigation history was empty.
//
// No problem, just ignore the exception.
}
}
/// <summary>
/// Navigates to the kanji referred by the given character.
/// Filters using the referred vocab kanji writing string.
/// Writes a navigation history entry to trace back to the
/// navigation state active before the operation.
/// </summary>
/// <param name="character">
/// Character driving the navigation.</param>
public void Navigate(KanjiWritingCharacter character)
{
if (KanjiDetailsVm != null)
{
// Temporarily unsubscribe the event.
KanjiDetailsVm.KanjiNavigated -= OnKanjiNavigated;
}
// Add the current state to the navigation history.
PushNavigationHistoryEntry();
// Create a new filter matching the vocab word selected.
_kanjiFilter = new KanjiFilter()
{
TextFilter = character.OriginalVocab.KanjiWriting,
// Ignore the levels because not only are they irrelevant,
// they might not even be the same for the kanji as for the vocab.
JlptLevel = Levels.IgnoreJlptLevel,
WkLevel = Levels.IgnoreWkLevel
};
// Apply the filter
KanjiFilterVm.SetFilter(_kanjiFilter);
KanjiListVm.Navigate(_kanjiFilter, character.Kanji);
// Create a new KanjiDetailsVm.
// Do not use the SetKanjiDetailsVm method as to not dispose
// the previous value.
KanjiDetailsVm = new KanjiDetailsViewModel(new ExtendedKanji(character.Kanji));
// Re-subscribe the event.
KanjiDetailsVm.KanjiNavigated += OnKanjiNavigated;
}