/// <summary>
/// ContentTargetSizeProperty property changed handler.
/// </summary>
/// <param name="d">AccordionItem that changed its ContentTargetSize.</param>
/// <param name="e">Event arguments.</param>
private static void OnContentTargetSizePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var source = (AccordionItem)d;
var targetSize = (Size)e.NewValue;
if (!source._allowedToWriteContentTargetSize)
{
// revert to old value
source.ContentTargetSize = (Size)e.OldValue;
throw new InvalidOperationException("Invalid content and size.");
}
// 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
#if SILVERLIGHT
expandSite.Percentage = 1;
#else
expandSite.RecalculatePercentage(1);
#endif
}
else
{
// otherwise schedule the resize
source.Schedule(AccordionAction.Resize);
}
}
}
}
/// <summary>
/// Recalculates the percentage based on a new size.
/// </summary>
/// <param name="expandableContentControl">The control which is going to be evaluated</param>
/// <param name="value">The new size used to base percentages on.</param>
/// <returns>The new percentage value</returns>
private static double CalculatePercentage(ExpandableContentControl expandableContentControl, Size value)
{
double newPercentage = 0.0;
if (expandableContentControl.ContentSite != null)
{
if (expandableContentControl.IsVerticalRevealMode)
{
newPercentage = expandableContentControl.ActualHeight /
(double.IsNaN(value.Height)
? expandableContentControl.ContentSite.DesiredSize.Height
: value.Height);
}
else if (expandableContentControl.IsHorizontalRevealMode)
{
newPercentage = expandableContentControl.ActualWidth /
(double.IsNaN(value.Width)
? expandableContentControl.ContentSite.DesiredSize.Width
: value.Width);
}
}
return(newPercentage);
}