/// <summary>
/// This method propagates the styles in the resources associated with
/// a framework element to its descendents. This results in a
/// style inheritance that mimics WPF's behavior.
/// </summary>
/// <param name="element">The element that will have its styles
/// propagated to its children.</param>
/// <param name="recurse">Whether to recurse over styled elements that
/// are set to OneTime and have already been styled.</param>
private static void PropagateStyles(FrameworkElement element, bool recurse)
{
BaseMergedStyleDictionary initialDictionary = GetMergedStyleDictionary(element);
// Create stream of elements and their base merged style
// dictionaries by traversing the logical tree.
IEnumerable <Tuple <FrameworkElement, BaseMergedStyleDictionary> > elementsToStyleAndDictionaries =
FunctionalProgramming.TraverseDepthFirst(
new Tuple <FrameworkElement, BaseMergedStyleDictionary>(element, initialDictionary),
(elementAndDictionary) =>
elementAndDictionary
.First
.GetLogicalChildrenDepthFirst()
.Select(childElement =>
new Tuple <FrameworkElement, BaseMergedStyleDictionary>(
childElement,
new MergedStyleResourceDictionary(
ImplicitStyleManager.GetExternalResourceDictionary(childElement) ?? childElement.Resources,
elementAndDictionary.Second))),
(elementAndDictionary) => recurse ||
(ImplicitStyleManager.GetApplyMode(elementAndDictionary.First) != ImplicitStylesApplyMode.OneTime ||
!ImplicitStyleManager.GetHasBeenStyled(elementAndDictionary.First)));
foreach (Tuple <FrameworkElement, BaseMergedStyleDictionary> elementToStyleAndDictionary in elementsToStyleAndDictionaries)
{
FrameworkElement elementToStyle = elementToStyleAndDictionary.First;
BaseMergedStyleDictionary styleDictionary = elementToStyleAndDictionary.Second;
bool styleApplied = false;
if (elementToStyle.Style == null || GetStyle(elementToStyle) == elementToStyle.Style)
{
Style style = styleDictionary[GetStyleKey(elementToStyle)];
if (style != null)
{
SetStyle(elementToStyle, style);
styleApplied = true;
}
}
if (ImplicitStyleManager.GetApplyMode(elementToStyle) == ImplicitStylesApplyMode.OneTime && (VisualTreeHelper.GetChildrenCount(elementToStyle) > 0 || styleApplied))
{
ImplicitStyleManager.SetHasBeenStyled(elementToStyle, true);
}
}
}
/// <summary>
/// ApplyModeProperty property changed handler.
/// </summary>
/// <param name="dependencyObject">FrameworkElement that changed its
/// ApplyMode.</param>
/// <param name="eventArgs">Event arguments.</param>
private static void OnApplyModePropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs eventArgs)
{
FrameworkElement element = dependencyObject as FrameworkElement;
if (element == null)
{
throw new ArgumentNullException("dependencyObject");
}
ImplicitStylesApplyMode oldMode = (ImplicitStylesApplyMode)eventArgs.OldValue;
ImplicitStylesApplyMode newMode = (ImplicitStylesApplyMode)eventArgs.NewValue;
ImplicitStyleManager.SetHasBeenStyled(element, false);
EventHandler eventHandler = ImplicitStyleManager.GetLayoutUpdatedHandler(element);
// If element is automatically styled (once or always) attach event
// handler.
if ((newMode == ImplicitStylesApplyMode.Auto || newMode == ImplicitStylesApplyMode.OneTime) &&
oldMode == ImplicitStylesApplyMode.None)
{
if (eventHandler == null)
{
eventHandler =
(sender, args) =>
{
ImplicitStyleManager.PropagateStyles(element, false);
};
ImplicitStyleManager.SetLayoutUpdatedHandler(element, eventHandler);
element.LayoutUpdated += eventHandler;
}
}
else if ((oldMode == ImplicitStylesApplyMode.Auto || oldMode == ImplicitStylesApplyMode.OneTime) &&
newMode == ImplicitStylesApplyMode.None)
{
if (eventHandler != null)
{
element.LayoutUpdated -= eventHandler;
ImplicitStyleManager.SetLayoutUpdatedHandler(element, null);
}
}
}
