优化更新代码，添加界面功能并整合

WPFluent/Controls/IconElement/IconElement.cs

@@ -0,0 +1,106 @@
+using WPFluent.Converters;
+
+using System.Windows.Controls;
+using System.Windows.Documents;
+using System.Windows.Input;
+
+// ReSharper disable once CheckNamespace
+namespace WPFluent.Controls;
+
+/// <summary>
+/// Represents the base class for an icon UI element.
+/// </summary>
+[TypeConverter(typeof(IconElementConverter))]
+public abstract class IconElement : FrameworkElement
+{
+    /// <summary>
+    /// Identifies the <see cref="Foreground"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty ForegroundProperty = TextElement.ForegroundProperty
+        .AddOwner(
+            typeof(IconElement),
+            new FrameworkPropertyMetadata(
+                SystemColors.ControlTextBrush,
+                FrameworkPropertyMetadataOptions.Inherits,
+                static(d, args) => ((IconElement)d).OnForegroundChanged(args)));
+
+    private Grid? _layoutRoot;
+
+    static IconElement()
+    {
+        FocusableProperty.OverrideMetadata(typeof(IconElement), new FrameworkPropertyMetadata(false));
+        KeyboardNavigation.IsTabStopProperty.OverrideMetadata(typeof(IconElement), new FrameworkPropertyMetadata(false));
+    }
+
+    private void EnsureLayoutRoot()
+    {
+        if(_layoutRoot != null)
+        {
+            return;
+        }
+
+        _layoutRoot = new Grid { Background = Brushes.Transparent, SnapsToDevicePixels = true };
+
+        _ = _layoutRoot.Children.Add(InitializeChildren());
+
+        AddVisualChild(_layoutRoot);
+    }
+
+    protected override Size ArrangeOverride(Size finalSize)
+    {
+        EnsureLayoutRoot();
+
+        _layoutRoot!.Arrange(new Rect(default, finalSize));
+        return finalSize;
+    }
+
+    protected override Visual GetVisualChild(int index)
+    {
+        if(index != 0)
+        {
+            throw new ArgumentOutOfRangeException(nameof(index), "IconElement should have only 1 child");
+        }
+
+        EnsureLayoutRoot();
+        return _layoutRoot!;
+    }
+
+    protected abstract UIElement InitializeChildren();
+
+    protected override Size MeasureOverride(Size availableSize)
+    {
+        EnsureLayoutRoot();
+
+        _layoutRoot!.Measure(availableSize);
+        return _layoutRoot.DesiredSize;
+    }
+
+    protected virtual void OnForegroundChanged(DependencyPropertyChangedEventArgs args)
+    {
+    }
+
+    protected override int VisualChildrenCount => 1;
+
+    /// <summary>
+    /// Coerces the value of an Icon dependency property, allowing the use of either IconElement or IconSourceElement.
+    /// </summary>
+    /// <param name="_">The dependency object (unused).</param>
+    /// <param name="baseValue">The value to be coerced.</param>
+    /// <returns>An IconElement, either directly or derived from an IconSourceElement.</returns>
+    public static object? Coerce(DependencyObject _, object? baseValue)
+    {
+        return baseValue switch
+        {
+            IconSourceElement iconSourceElement => iconSourceElement.CreateIconElement(),
+            IconElement or null => baseValue,
+            _ => throw new ArgumentException(
+                message: $"Expected either '{typeof(IconSourceElement)}' or '{typeof(IconElement)}' but got '{baseValue.GetType()}'.",
+                paramName: nameof(baseValue)),
+        };
+    }
+
+    /// <inheritdoc cref="Control.Foreground"/>
+    [Bindable(true)]
+    [Category("Appearance")]
+    public Brush Foreground { get => (Brush)GetValue(ForegroundProperty); set => SetValue(ForegroundProperty, value); }
+}