<Window x:Class="WpfImplicitStyle.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <Grid>
        <Grid.Resources>
            <!-- 针对一种类型设置全局样式 -->
            <Style TargetType="Button">
                <Setter Property="Background" Value="AliceBlue" /> 
            </Style>
        </Grid.Resources>
        <StackPanel>
            <Button>Button a</Button>
            <Button>Button b</Button>
        </StackPanel>
    </Grid>
</Window>

<UserControl x:Class="ImplicitStyleTest.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Width="400" Height="300"
        xmlns:theming="clr-namespace:Microsoft.Windows.Controls.Theming;assembly=Microsoft.Windows.Controls.Theming">
    <Grid x:Name="LayoutRoot" Background="White">
        <Grid.Resources>
            <Style TargetType="Button">
                <Setter Property="Background" Value="AliceBlue" />
            </Style>
        </Grid.Resources>
        <!-- 在根元素上设置一次就可以了 -->
        <StackPanel theming:ImplicitStyleManager.ApplyMode="Auto">
            <Button Content="Button a"></Button>
            <Button Content="Button b"></Button>
        </StackPanel>
    </Grid>
</UserControl>

/// <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);
        }
    }
}

/// <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.Traverse(
            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)
        {
            Style style = styleDictionary[GetStyleKey(elementToStyle)];
            if (style != null)
            {
                elementToStyle.Style = style;
                styleApplied = true;
            }
        }

if (ImplicitStyleManager.GetApplyMode(elementToStyle) == ImplicitStylesApplyMode.OneTime && (VisualTreeHelper.GetChildrenCount(elementToStyle) > 0 || styleApplied))
        {
            ImplicitStyleManager.SetHasBeenStyled(elementToStyle, true);
        }
    }
}