/// <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>
/// Retrieves all the logical children of a framework element using a
/// depth-first search. A visual element is assumed to be a logical
/// child of another visual element if they are in the same namescope.
/// For performance reasons this method manually manages the stack
/// instead of using recursion.
/// </summary>
/// <param name="parent">The parent framework element.</param>
/// <returns>The logical children of the framework element.</returns>
internal static IEnumerable <FrameworkElement> GetLogicalChildrenDepthFirst(this FrameworkElement parent)
{
Debug.Assert(parent != null, "The parent cannot be null.");
EnsureName(parent);
Popup popup = parent as Popup;
if (popup != null)
{
FrameworkElement popupChild = popup.Child as FrameworkElement;
if (popupChild != null)
{
yield return(popupChild);
}
}
// If control is an items control find the items host panel and
// return it if an ItemsPanel template is specified. This works
// around a bug which moves the items host into a different name
// scope than the items control when an items template is provided.
ItemsControl itemsControl = parent as ItemsControl;
if (itemsControl != null && itemsControl.ItemsPanel != null)
{
ItemsPresenter itemsPresenter =
itemsControl
.GetVisualChildren()
.SelectMany(child =>
FunctionalProgramming.TraverseBreadthFirst(
child,
node => node.GetVisualChildren(),
node => !(node is ItemsControl)))
.OfType <ItemsPresenter>()
.FirstOrDefault();
if (itemsPresenter != null)
{
Panel itemsHost = itemsPresenter.GetVisualChildren().OfType <Panel>().FirstOrDefault();
if (itemsHost != null)
{
yield return(itemsHost);
}
}
}
string parentName = parent.Name;
Stack <FrameworkElement> stack =
new Stack <FrameworkElement>(parent.GetVisualChildren().OfType <FrameworkElement>());
while (stack.Count > 0)
{
FrameworkElement element = stack.Pop();
if (element.FindName(parentName) == parent || element is UserControl)
{
yield return(element);
}
else
{
foreach (FrameworkElement visualChild in element.GetVisualChildren().OfType <FrameworkElement>())
{
stack.Push(visualChild);
}
}
}
}
