优化更新代码，添加界面功能并整合

WPFluent/Controls/Flyout/FlyoutService.cs

@@ -0,0 +1,186 @@
+using System.Reflection;
+using System.Windows;
+using System.Windows.Input;
+
+namespace WPFluent.Controls;
+
+/// <summary>
+/// <seealso cref="Flyout"/>
+/// </summary>
+/// <example>
+/// <code lang="xml">
+/// <ui:Button Content = "Show Flyout" >
+///    < ui:FlyoutService.Flyout>
+///        <ui:Flyout Placement = "Bottom" >
+///            < StackPanel >
+///                < TextBlock
+///                    HorizontalAlignment="Left"
+///                    Text="Show the flyout message here" />
+///                 <Button
+///                   Command = "{Binding GotItCommand}"
+///                   Content="Got it" />
+///            </StackPanel>
+///        </ui:Flyout>
+///    </ui:FlyoutService.Flyout>
+///</ui:Button>
+///</code>
+/// </example>
+public static class FlyoutService
+{
+    public static Flyout GetFlyout(DependencyObject obj)
+    {
+        return (obj.GetValue(FlyoutProperty) as Flyout)!;
+    }
+
+    public static void SetFlyout(DependencyObject obj, Flyout value)
+    {
+        obj.SetValue(FlyoutProperty, value);
+    }
+
+    public static readonly DependencyProperty FlyoutProperty =
+        DependencyProperty.RegisterAttached("Flyout", typeof(Flyout), typeof(FlyoutService), new(null, OnFlyoutChanged));
+
+    public static void OnFlyoutChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+    {
+        if (d is FrameworkElement buttonExpected)
+        {
+            if (e.NewValue is Flyout flyout)
+            {
+                // Inherit data context.
+                flyout.DataContext = buttonExpected.DataContext;
+
+                buttonExpected.DataContextChanged -= ButtonExpectedDataContextChanged;
+                buttonExpected.DataContextChanged += ButtonExpectedDataContextChanged;
+            }
+
+            // Binding click or leftmouse event to show flyout.
+            {
+                if (d is Button button)
+                {
+                    button.Click -= ShowFlyoutRequested;
+                    button.Click += ShowFlyoutRequested;
+                    return;
+                }
+            }
+            {
+                if (d is System.Windows.Controls.Button button)
+                {
+                    button.Click -= ShowFlyoutRequested;
+                    button.Click += ShowFlyoutRequested;
+                    return;
+                }
+            }
+            {
+                buttonExpected.MouseLeftButtonUp -= ShowFlyoutRequested;
+                buttonExpected.MouseLeftButtonUp += ShowFlyoutRequested;
+            }
+        }
+    }
+
+    private static void ButtonExpectedDataContextChanged(object? sender, DependencyPropertyChangedEventArgs e)
+    {
+        if (sender is FrameworkElement buttonExpected)
+        {
+            if (GetFlyout(buttonExpected) is Flyout flyout)
+            {
+                // Inherit data context.
+                flyout.DataContext = buttonExpected.DataContext;
+            }
+        }
+    }
+
+    private static void ShowFlyoutRequested(object? sender, RoutedEventArgs e)
+    {
+        if (sender is FrameworkElement buttonExpected)
+        {
+            ShowFlyout(buttonExpected);
+        }
+    }
+
+    private static void ShowFlyoutRequested(object? sender, MouseButtonEventArgs e)
+    {
+        if (sender is FrameworkElement buttonExpected)
+        {
+            ShowFlyout(buttonExpected);
+        }
+    }
+
+    public static void ShowFlyout(FrameworkElement buttonExpected)
+    {
+        if (GetFlyout(buttonExpected) is Flyout flyout)
+        {
+            // Get the flyout popup from Flyout control default template.
+            flyout.ApplyTemplate();
+            if (flyout.GetTemplateChild("PART_Popup") is System.Windows.Controls.Primitives.Popup popup)
+            {
+                // Inherit data context.
+                popup.DataContext = flyout.DataContext;
+
+                // Reset the popup placement.
+                popup.PlacementTarget = buttonExpected;
+                popup.Placement = flyout.Placement;
+
+                // Remove the popup parent
+                if (popup.Parent is System.Windows.Controls.Panel parent)
+                {
+                    parent.Children.Remove(popup);
+                }
+
+                // Set the flyout parent
+                if (flyout.Parent is null)
+                {
+                    // Find nearest panel
+                    if (buttonExpected.Parent is System.Windows.Controls.Panel parent2)
+                    {
+                        parent2.Children.Add(flyout);
+                    }
+                    // Once fallback to window top level
+                    else if (Window.GetWindow(buttonExpected)?.Content is System.Windows.Controls.Panel parent3)
+                    {
+                        parent3.Children.Add(flyout);
+                    }
+                    else
+                    {
+                        // Flyout is not added to any parent.
+                        // Flyout will be shown but the theme is not synced.
+                        // See more https://github.com/emako/wpfui.violeta/issues/10.
+                    }
+                }
+
+                // Following code is based on the Flyout control default template.
+                // If default template is changed, this code will not work.
+                // Check WPF-UI v3.0.5 since.
+                if (flyout.Content is not null)
+                {
+                    UIElement? contentElement = flyout.Content as UIElement;
+                    flyout.Content = null;
+                    ((System.Windows.Controls.Border)popup.Child).Child = contentElement;
+                }
+
+                // Spoof the flyout opening state.
+                flyout.IsOpen = popup.IsOpen = true;
+            }
+        }
+    }
+
+    public static void HideFlyout(FrameworkElement buttonExpected)
+    {
+        if (GetFlyout(buttonExpected) is Flyout flyout)
+        {
+            // Get the flyout popup from Flyout control default template.
+            if (flyout.GetTemplateChild("PART_Popup") is System.Windows.Controls.Primitives.Popup popup)
+            {
+                // Spoof the flyout opening state.
+                flyout.IsOpen = popup.IsOpen = false;
+            }
+        }
+    }
+
+    private static DependencyObject? GetTemplateChild(this FrameworkElement self, string childName)
+    {
+        MethodInfo? method = typeof(FrameworkElement)
+            .GetMethod("GetTemplateChild", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.InvokeMethod);
+
+        return method?.Invoke(self, [childName]) as DependencyObject;
+    }
+}