public async Task TransitionBackward(DependencyObject previousPage, DependencyObject newPage)
{
if (previousPage == null && newPage == null)
{
throw new InvalidOperationException();
}
if (previousPage == null)
{
await BackwardInAnimation.Animate(newPage);
}
else if (newPage == null)
{
await BackwardOutAnimation.Animate(previousPage);
}
else if (this.Mode == PageTransitionMode.Parallel)
{
var sb = new Storyboard();
var outSb = BackwardOutAnimation.GetAnimation(previousPage);
var inSb = BackwardInAnimation.GetAnimation(newPage);
sb.Children.Add(outSb);
sb.Children.Add(inSb);
await sb.BeginAsync();
sb.Stop();
sb.Children.Clear();
//await Task.WhenAll(
// BackwardOutAnimation.Animate(previousPage),
// BackwardInAnimation.Animate(newPage));
}
else
{
await BackwardOutAnimation.Animate(previousPage);
await BackwardInAnimation.Animate(newPage);
}
}
/// <summary>
/// Runs backward transition.
/// </summary>
/// <param name="previousPage">The previous page.</param>
/// <param name="newPage">The new page.</param>
/// <returns>The task that completes when the transition is complete.</returns>
/// <exception cref="System.ArgumentNullException"></exception>
public async Task TransitionBackward(DependencyObject previousPage, DependencyObject newPage)
{
if (previousPage == null && newPage == null)
{
throw new ArgumentNullException("newPage");
}
PrepareBackwardAnimations(previousPage, newPage);
UpdateTimelineAttributes();
if (previousPage == null)
{
await BackwardInAnimation.Animate(newPage);
}
else if (newPage == null)
{
await BackwardOutAnimation.Animate(previousPage);
}
else if (this.Mode == PageTransitionMode.Parallel)
{
var sb = new Storyboard();
Storyboard outSb = null;
Storyboard inSb = null;
if (this.BackwardOutAnimation != null)
{
outSb = this.BackwardOutAnimation.GetAnimation(previousPage);
sb.Children.Add(outSb);
}
if (this.BackwardInAnimation != null)
{
inSb = this.BackwardInAnimation.GetAnimation(newPage);
sb.Children.Add(inSb);
}
await sb.BeginAsync();
sb.Stop();
sb.Children.Clear();
if (this.BackwardOutAnimation != null)
{
this.BackwardOutAnimation.CleanupAnimation(previousPage, outSb);
}
if (this.BackwardInAnimation != null)
{
this.BackwardInAnimation.CleanupAnimation(newPage, inSb);
}
//await Task.WhenAll(
// BackwardOutAnimation.Animate(previousPage),
// BackwardInAnimation.Animate(newPage));
}
else
{
if (this.BackwardOutAnimation != null)
{
await this.BackwardOutAnimation.Animate(previousPage);
}
if (this.BackwardInAnimation != null)
{
await this.BackwardInAnimation.Animate(newPage);
}
}
CleanupBackwardAnimations(previousPage, newPage);
}
