/// <summary>
/// Retrieves or creates the merged style dictionary of an element.
/// </summary>
/// <param name="styledElement">A styled element.</param>
/// <returns>The merged dictionary of the element.</returns>
private static BaseMergedStyleDictionary GetMergedStyleDictionary(FrameworkElement styledElement)
{
Debug.Assert(styledElement != null, "styledElement cannot be null.");
IList <FrameworkElement> ancestorsInclusive = styledElement.GetVisualAncestors().Append(styledElement).Reverse().ToList();
IEnumerable <FrameworkElement> ancestorsTopToBottom = ancestorsInclusive;
BaseMergedStyleDictionary initialDictionary = null;
if (UseApplicationResources)
{
initialDictionary = new MergedStyleResourceDictionary(ApplicationExternalResourceDictionary ?? Application.Current.Resources);
}
else
{
FrameworkElement topLevelElement = ancestorsInclusive[0];
initialDictionary = new MergedStyleResourceDictionary(ImplicitStyleManager.GetExternalResourceDictionary(topLevelElement) ?? topLevelElement.Resources);
ancestorsTopToBottom = ancestorsInclusive.Skip(1);
}
BaseMergedStyleDictionary styleDictionary =
ancestorsTopToBottom.Aggregate(
initialDictionary,
(dictionary, ancestor) => new MergedStyleResourceDictionary(ImplicitStyleManager.GetExternalResourceDictionary(ancestor) ?? ancestor.Resources)
{
Parent = dictionary
});
return(styleDictionary);
}
/// <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>
/// Initializes a new instance of the MergedResourceDictionary class.
/// </summary>
/// <param name="resourceDictionary">A resource dictionary to check for
/// a value before checking the parent.</param>
/// <param name="parentResourceDictionary">The parent merged resource
/// dictionary to check if no match is found in the resource
/// dictionary.</param>
public MergedStyleResourceDictionary(ResourceDictionary resourceDictionary, BaseMergedStyleDictionary parentResourceDictionary)
{
Debug.Assert(resourceDictionary != null, "resourceDictionary cannot be null.");
_resourceDictionary = resourceDictionary;
Parent = parentResourceDictionary;
}
