/// <summary>
/// TargetSizeProperty property changed handler.
/// </summary>
/// <param name="dependencyObject">ExpandableContentControl that changed its TargetSize.</param>
/// <param name="e">Event arguments.</param>
private static void OnTargetSizePropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
{
ExpandableContentControl source = (ExpandableContentControl)dependencyObject;
Size value = (Size)e.NewValue;
// recalculate percentage based on this new targetsize.
// for instance, percentage was at 1 and width was 100. Now width was changed to 200, this means
// that the percentage needs to be set to 0.5 so that a reveal animation can be started again.
// We are essentially trying to re-evaluate the percentage property based on another property having changed,
// which is exactly what the coerce functionality of dependency properties is for
source.RecalculatePercentage(double.NaN);
}
/// <summary>
/// ContentTargetSizeProperty property changed handler.
/// </summary>
/// <param name="dependencyObject">AccordionItem that changed its ContentTargetSize.</param>
/// <param name="e">Event arguments.</param>
private static void OnContentTargetSizePropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
{
AccordionItem source = (AccordionItem)dependencyObject;
Size targetSize = (Size)e.NewValue;
if (!source.allowedToWriteContentTargetSize)
{
// revert to old value
source.ContentTargetSize = (Size)e.OldValue;
throw new InvalidOperationException(AccordionResources.AccordionItem_InvalidWriteToContentTargetSize);
}
// Pass the value to the expandSite
// This is done explicitly so an animation action can be scheduled
// deterministicly.
ExpandableContentControl expandSite = source.ExpandSite;
if (expandSite != null && !expandSite.TargetSize.Equals(targetSize))
{
expandSite.TargetSize = targetSize;
if (source.IsSelected)
{
if (source.ParentAccordion != null && source.ParentAccordion.IsResizing)
{
// if the accordion is resizing, this item should snap immediately
expandSite.RecalculatePercentage(1);
}
else
{
// otherwise schedule the resize
source.Schedule(AccordionAction.Resize);
}
}
}
}