public override void OnApplyTemplate()
{
if (this.IsTransitioning)
{
this.AbortTransition();
}
if (this.CustomVisualStates != null && this.CustomVisualStates.Any())
{
var presentationGroup = VisualStates.TryGetVisualStateGroup(this, PresentationGroup);
if (presentationGroup != null)
{
foreach (var state in this.CustomVisualStates)
{
presentationGroup.States.Add(state);
}
}
}
base.OnApplyTemplate();
this.previousContentPresentationSite = this.GetTemplateChild(PreviousContentPresentationSitePartName) as ContentPresenter;
this.currentContentPresentationSite = this.GetTemplateChild(CurrentContentPresentationSitePartName) as ContentPresenter;
// hookup currenttransition
Storyboard transition = this.GetStoryboard(this.Transition);
this.CurrentTransition = transition;
if (transition == null)
{
var invalidTransition = this.Transition;
// revert to default
this.Transition = DefaultTransitionState;
throw new MahAppsException($"'{invalidTransition}' transition could not be found!");
}
VisualStateManager.GoToState(this, HiddenState, false);
}
private static void OnTransitionPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var source = (TransitioningContentControl)d;
var oldTransition = (TransitionType)e.OldValue;
var newTransition = (TransitionType)e.NewValue;
if (source.IsTransitioning)
{
source.AbortTransition();
}
// find new transition
Storyboard newStoryboard = source.GetStoryboard(newTransition);
// unable to find the transition.
if (newStoryboard == null)
{
// could be during initialization of xaml that presentationgroups was not yet defined
if (VisualStates.TryGetVisualStateGroup(source, PresentationGroup) == null)
{
// will delay check
source.CurrentTransition = null;
}
else
{
// revert to old value
source.SetValue(TransitionProperty, oldTransition);
throw new ArgumentException(
string.Format(CultureInfo.CurrentCulture, "Temporary removed exception message", newTransition));
}
}
else
{
source.CurrentTransition = newStoryboard;
}
}