private void BeginTransition()
{
TransitionSelector selector = TransitionSelector;
Transition transition = selector != null ?
selector.SelectTransition(CurrentContentPresenter.Content, Content) :
Transition;
if (transition != null)
{
// Swap content presenters
AdornerDecorator temp = _previousHost;
_previousHost = _currentHost;
_currentHost = temp;
}
ContentPresenter currentContent = CurrentContentPresenter;
// Set the current content
currentContent.Content = Content;
currentContent.ContentTemplate = ContentTemplate;
currentContent.ContentTemplateSelector = ContentTemplateSelector;
if (transition != null)
{
ContentPresenter previousContent = PreviousContentPresenter;
if (transition.IsNewContentTopmost)
Children.Add(_currentHost);
else
Children.Insert(0, _currentHost);
IsTransitioning = true;
_activeTransition = transition;
CoerceValue(TransitionProperty);
CoerceValue(ClipToBoundsProperty);
transition.BeginTransition(this, previousContent, currentContent);
}
}
// Clean up after the transition is complete
internal void OnTransitionCompleted()
{
_children.Clear();
_children.Add(_currentHost);
_currentHost.Visibility = Visibility.Visible;
_previousHost.Visibility = Visibility.Visible;
((ContentPresenter)_previousHost.Child).Content = null;
IsTransitioning = false;
_activeTransition = null;
CoerceValue(TransitionProperty);
CoerceValue(ClipToBoundsProperty);
CoerceValue(ContentProperty);
}
