/// <summary>
/// RevealModeProperty property changed handler.
/// </summary>
/// <param name="dependencyObject">ExpandableContentControl that changed its RevealMode.</param>
/// <param name="e">Event arguments.</param>
private static void OnRevealModePropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
{
ExpandableContentControl source = (ExpandableContentControl)dependencyObject;
ExpandDirection value = (ExpandDirection)e.NewValue;
if (value != ExpandDirection.Down &&
value != ExpandDirection.Left &&
value != ExpandDirection.Right &&
value != ExpandDirection.Up)
{
// revert to old value
source.RevealMode = (ExpandDirection)e.OldValue;
string message = string.Format(
CultureInfo.InvariantCulture,
AccordionResources.Expander_OnExpandDirectionPropertyChanged_InvalidValue,
value);
throw new ArgumentException(message, "e");
}
// set the non-reveal dimension
source.SetNonRevealDimension();
// calculate the reveal dimension
source.SetRevealDimension();
}
/// <summary>
/// PercentageProperty property changed handler.
/// </summary>
/// <param name="dependencyObject">Page that changed its Percentage.</param>
/// <param name="e">Event arguments.</param>
private static void OnPercentagePropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
{
ExpandableContentControl source = (ExpandableContentControl)dependencyObject;
source.SetRevealDimension();
source.InvalidateMeasure();
}
/// <summary>
/// Coerce the percentage property as necessary.
/// </summary>
/// <param name="dependencyObject">The dependency object.</param>
/// <param name="baseValue">The base value.</param>
/// <returns>The coerced value.</returns>
private static object CoercePercentageProperty(DependencyObject dependencyObject, object baseValue)
{
// This works around a subtle difference between WPF 3 and SL 3,
// where a value assigned to a dependency property from within the control
// is considered to be from a local source, and trumps styles/templates from that point forward.
// This could be worked around in WPF 4.0 with DependencyObject.SetCurrentValue()
object returnValue = baseValue;
ExpandableContentControl expandableContentControl = dependencyObject as ExpandableContentControl;
// This method can be called by a parent control through RecalculatePercentage(double)
// To know when to coerce and avoid having to do so more than needed, calculatePercentage can have 3 states:
// Null: Don't corce using internal value, simply return baseValue
// Double.NAN: Coerce by computing new percentage value based on current target size
// value: Corece by returning explicit value previously set in RecalculatePercentage(double)
if (expandableContentControl != null && expandableContentControl.calculatePercentage.HasValue)
{
if (double.IsNaN(expandableContentControl.calculatePercentage.Value))
{
returnValue = CalculatePercentage(expandableContentControl, expandableContentControl.TargetSize);
}
else
{
returnValue = expandableContentControl.calculatePercentage.Value;
}
expandableContentControl.calculatePercentage = null;
}
return(returnValue);
}
/// <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>
/// 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);
}
/// <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);
}
}
}
}
/// <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;
}
