优化更新代码，添加界面功能并整合

WPFluent/Controls/ContentDialog/ClientAreaBorder.cs

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+
+
+
+using WPFluent.Appearance;
+using WPFluent.Hardware;
+
+using System.Windows.Shell;
+
+using Size = System.Windows.Size;
+
+// ReSharper disable once CheckNamespace
+namespace WPFluent.Controls;
+
+/// <summary>
+/// If you use <see cref="WindowChrome"/> to extend the UI elements to the non-client area, you can include this
+/// container in the template of <see cref="Window"/> so that the content inside automatically fills the client area.
+/// Using this container can let you get rid of various margin adaptations done in Setter/Trigger of the style of <see
+/// cref="Window"/> when the window state changes.
+/// </summary>
+/// <example>
+/// <code lang="xml"> &lt;Style x:Key="MyWindowCustomStyle" BasedOn="{StaticResource {x:Type Window}}"
+/// TargetType="{x:Type controls:FluentWindow}"&gt; &lt;Setter Property="Template" &gt; &lt;Setter.Value&gt;
+/// &lt;ControlTemplate TargetType="{x:Type Window}"&gt; &lt;AdornerDecorator&gt; &lt;controls:ClientAreaBorder
+/// Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}"
+/// BorderThickness="{TemplateBinding BorderThickness}"&gt; &lt;ContentPresenter x:Name="ContentPresenter" /&gt;
+/// &lt;/controls:ClientAreaBorder&gt; &lt;/AdornerDecorator&gt; &lt;/ControlTemplate&gt; &lt;/Setter.Value&gt;
+/// &lt;/Setter&gt; &lt;/Style&gt;</code>
+/// </example>
+public class ClientAreaBorder : System.Windows.Controls.Border, IThemeControl
+{
+    /*private const int SM_CXFRAME = 32;
+    private const int SM_CYFRAME = 33;
+    private const int SM_CXPADDEDBORDER = 92;*/
+    private static Thickness? _paddedBorderThickness;
+    private static Thickness? _resizeFrameBorderThickness;
+    private static Thickness? _windowChromeNonClientFrameThickness;
+    private bool _borderBrushApplied = false;
+    private System.Windows.Window? _oldWindow;
+
+    public ClientAreaBorder()
+    {
+        ApplicationTheme = Appearance.ApplicationThemeManager.GetAppTheme();
+        Appearance.ApplicationThemeManager.Changed += OnThemeChanged;
+    }
+
+    private void ApplyDefaultWindowBorder()
+    {
+        if(Win32.Utilities.IsOSWindows11OrNewer || _oldWindow == null)
+        {
+            return;
+        }
+
+        _borderBrushApplied = true;
+
+        // SystemParameters.WindowGlassBrush
+        Color borderColor =
+            ApplicationTheme == ApplicationTheme.Light
+            ? Color.FromArgb(0xFF, 0x7A, 0x7A, 0x7A)
+            : Color.FromArgb(0xFF, 0x3A, 0x3A, 0x3A);
+        _oldWindow.SetCurrentValue(
+            System.Windows.Controls.Control.BorderBrushProperty,
+            new SolidColorBrush(borderColor));
+        _oldWindow.SetCurrentValue(System.Windows.Controls.Control.BorderThicknessProperty, new Thickness(1));
+    }
+
+    private (double FactorX, double FactorY) GetDpi()
+    {
+        if(PresentationSource.FromVisual(this) is { } source)
+        {
+            return (
+                source.CompositionTarget.TransformToDevice.M11, // Possible null reference
+                source.CompositionTarget.TransformToDevice.M22
+            );
+        }
+
+        DisplayDpi systemDPi = DpiHelper.GetSystemDpi();
+
+        return (systemDPi.DpiScaleX, systemDPi.DpiScaleY);
+    }
+
+    private void OnThemeChanged(ApplicationTheme currentApplicationTheme, Color systemAccent)
+    {
+        ApplicationTheme = currentApplicationTheme;
+
+        if(!_borderBrushApplied || _oldWindow == null)
+        {
+            return;
+        }
+
+        ApplyDefaultWindowBorder();
+    }
+
+    private void OnWindowClosing(object? sender, CancelEventArgs e)
+    {
+        Appearance.ApplicationThemeManager.Changed -= OnThemeChanged;
+        if(_oldWindow != null)
+        {
+            _oldWindow.Closing -= OnWindowClosing;
+        }
+    }
+
+    private void OnWindowStateChanged(object? sender, EventArgs e)
+    {
+        if(sender is not System.Windows.Window window)
+        {
+            return;
+        }
+
+        Thickness padding =
+            window.WindowState == WindowState.Maximized ? WindowChromeNonClientFrameThickness : default;
+        SetCurrentValue(PaddingProperty, padding);
+    }
+
+    /// <inheritdoc/>
+    protected override void OnVisualParentChanged(DependencyObject oldParent)
+    {
+        base.OnVisualParentChanged(oldParent);
+
+        if(_oldWindow is { } oldWindow)
+        {
+            oldWindow.StateChanged -= OnWindowStateChanged;
+            oldWindow.Closing -= OnWindowClosing;
+        }
+
+        var newWindow = System.Windows.Window.GetWindow(this);
+
+        if(newWindow is not null)
+        {
+            newWindow.StateChanged -= OnWindowStateChanged; // Unsafe
+            newWindow.StateChanged += OnWindowStateChanged;
+            newWindow.Closing += OnWindowClosing;
+        }
+
+        _oldWindow = newWindow;
+
+        ApplyDefaultWindowBorder();
+    }
+
+    public ApplicationTheme ApplicationTheme { get; set; } = ApplicationTheme.Unknown;
+
+    /// <summary>
+    /// Gets the system value for the padded border thickness (<see cref="User32.SM.CXPADDEDBORDER"/>) in WPF units.
+    /// </summary>
+    public Thickness PaddedBorderThickness
+    {
+        get
+        {
+            if(_paddedBorderThickness is not null)
+            {
+                return _paddedBorderThickness.Value;
+            }
+
+            var paddedBorder = Interop.User32.GetSystemMetrics(Interop.User32.SM.CXPADDEDBORDER);
+
+            (double factorX, double factorY) = GetDpi();
+
+            var frameSize = new Size(paddedBorder, paddedBorder);
+            var frameSizeInDips = new Size(frameSize.Width / factorX, frameSize.Height / factorY);
+
+            _paddedBorderThickness = new Thickness(
+                frameSizeInDips.Width,
+                frameSizeInDips.Height,
+                frameSizeInDips.Width,
+                frameSizeInDips.Height);
+
+            return _paddedBorderThickness.Value;
+        }
+    }
+
+    /// <summary>
+    /// Gets the system <see cref="User32.SM.CXFRAME"/> and <see cref="User32.SM.CYFRAME"/> values in WPF units.
+    /// </summary>
+    public static Thickness ResizeFrameBorderThickness => _resizeFrameBorderThickness ??= new Thickness(
+        SystemParameters.ResizeFrameVerticalBorderWidth,
+        SystemParameters.ResizeFrameHorizontalBorderHeight,
+        SystemParameters.ResizeFrameVerticalBorderWidth,
+        SystemParameters.ResizeFrameHorizontalBorderHeight);
+
+    /// <summary>
+    /// Gets the thickness of the window's non-client frame used for maximizing the window with a custom chrome.
+    /// </summary>
+    /// <remarks>
+    /// If you use a <see cref="WindowChrome"/> to extend the client area of a window to the non-client area, you need
+    /// to handle the edge margin issue when the window is maximized. Use this property to get the correct margin value
+    /// when the window is maximized, so that when the window is maximized, the client area can completely cover the
+    /// screen client area by no less than a single pixel at any DPI. The<see cref="User32.GetSystemMetrics"/> method
+    /// cannot obtain this value directly.
+    /// </remarks>
+    public Thickness WindowChromeNonClientFrameThickness => _windowChromeNonClientFrameThickness ??= new Thickness(
+        ClientAreaBorder.ResizeFrameBorderThickness.Left + PaddedBorderThickness.Left,
+        ClientAreaBorder.ResizeFrameBorderThickness.Top + PaddedBorderThickness.Top,
+        ClientAreaBorder.ResizeFrameBorderThickness.Right + PaddedBorderThickness.Right,
+        ClientAreaBorder.ResizeFrameBorderThickness.Bottom + PaddedBorderThickness.Bottom);
+}