void TransitionCompleted(object sender, EventArgs e)
{
VideoStoryCreator.Transitions.ITransition transition = (VideoStoryCreator.Transitions.ITransition)sender;
// 如果没有被transition修改，则修改z-index.
if (!transition.ImageZIndexModified)
{
this.backgroundImage.SetValue(Canvas.ZIndexProperty, 2);
this.foregroundImage.SetValue(Canvas.ZIndexProperty, 0);
}
transition.Stop();
this.GoToNext();
}
void DispatcherTimer_Tick(object sender, EventArgs e)
{
this.backgroundImage.Opacity = 1;
VideoStoryCreator.Transitions.ITransition transition = App.MediaCollection[this._currentImageIndex - 1].Transition;
// 显示transition若它不为空.
// 这个task被委托到transition类.
if (transition != null)
{
transition.ForegroundElement = this.foregroundImage;
transition.BackgroundElement = this.backgroundImage;
transition.TransitionCompleted += new EventHandler(TransitionCompleted);
transition.Begin();
this._dispatcherTimer.Stop();
}
// 没有transition，从下张图片开始.
else
{
this._dispatcherTimer.Stop();
this.backgroundImage.SetValue(Canvas.ZIndexProperty, 2);
this.foregroundImage.SetValue(Canvas.ZIndexProperty, 0);
this.GoToNext();
}
}
