private void CurrentViewModel_ChangeScreen(IScreen screen, eTransitionType transitionType)
{
CurrentViewModel.ChangeScreen -= CurrentViewModel_ChangeScreen;
if (CurrentViewModel is HomeViewModel)
{
(CurrentViewModel as HomeViewModel).ShowDialog -= CurrentViewModel_ShowDialog;
}
Transition = TransitionSelector.Get(transitionType);
CurrentViewModel = screen;
CurrentViewModel.ChangeScreen += CurrentViewModel_ChangeScreen;
if (CurrentViewModel is HomeViewModel)
{
(CurrentViewModel as HomeViewModel).ShowDialog += CurrentViewModel_ShowDialog;
}
}
public static void SetTransitionSelector(DependencyObject target, TransitionSelector value)
{
target.SetValue(TransitionSelectorProperty, value);
}
/// <summary>
/// Starts the selected <see cref="Transition"/>.
/// </summary>
public void BeginTransition()
{
Debug.WriteLineIf(TraceSwitches.Transitions.TraceVerbose, "TransitionElement - BeginTransition Entry");
Debug.WriteLineIf(TraceSwitches.Transitions.TraceVerbose, "TransitionElement - effectiveContent using direct content");
object newContent = this.Content;
ContentPresenter existingContentPresenter = this.NewContentPresenter;
object oldContent = existingContentPresenter.Content;
TransitionSelector transitionSelector = this.TransitionSelector;
Transition transition = this.Transition;
if (transitionSelector != null)
{
transition = transitionSelector.SelectTransition(oldContent, newContent);
}
bool transitioningToNullContent = newContent == null;
bool transitioningFromNullContent = oldContent == null;
Debug.WriteLineIf(TraceSwitches.Transitions.TraceVerbose && transition != null, "TransitionElement - BeginTransition transition is set");
Debug.WriteLineIf(TraceSwitches.Transitions.TraceVerbose && transition == null, "TransitionElement - BeginTransition transition is null");
bool shouldTransition = (transition != null) && (TransitionsEnabled) && (!SkipTransition(transition, existingContentPresenter, transitioningToNullContent, transitioningFromNullContent));
if (shouldTransition)
{
Debug.WriteLineIf(TraceSwitches.Transitions.TraceVerbose, "TransitionElement - BeginTransition Swapping content presenters");
// Swap content presenters
ContentPresenter temp = this._oldContentPresenter;
this._oldContentPresenter = this._newContentPresenter;
this._newContentPresenter = temp;
}
Debug.WriteLineIf(TraceSwitches.Transitions.TraceVerbose, "TransitionElement - BeginTransition Updating current content presenter's content");
ContentPresenter newContentPresenter = this.NewContentPresenter;
// Set the current content
newContentPresenter.Content = newContent;
newContentPresenter.ContentTemplate = this.ContentTemplate;
newContentPresenter.ContentTemplateSelector = this.ContentTemplateSelector;
if (shouldTransition)
{
ContentPresenter oldContentPresenter = this.OldContentPresenter;
if (oldContent == null && this.NullContentTemplate != null)
{
oldContentPresenter.ContentTemplate = this.NullContentTemplate;
}
if (newContent == null && this.NullContentTemplate != null)
{
newContentPresenter.ContentTemplate = this.NullContentTemplate;
}
if (transition.IsNewContentTopmost)
{
this.Children.Add(this._newContentPresenter);
}
else
{
this.Children.Insert(0, this._newContentPresenter);
}
Debug.WriteLineIf(TraceSwitches.Transitions.TraceVerbose, "TransitionElement - BeginTransition Setting up for transition");
this.IsTransitioning = true;
this.activeTransition = transition;
CoerceValue(TransitionProperty);
CoerceValue(ClipToBoundsProperty);
OnTransitionBeginning(new TransitionEventArgs(TransitionBeginningEvent, this, transition, oldContent, newContent));
Debug.WriteLineIf(TraceSwitches.Transitions.TraceVerbose, "TransitionElement - BeginTransition Calling transition's BeginTransition");
transition.BeginTransition(this, oldContentPresenter, newContentPresenter);
}
}
