优化更新代码，添加界面功能并整合

WPFluent/Controls/Card/Card.cs

@@ -0,0 +1,53 @@
+
+
+
+// ReSharper disable once CheckNamespace
+namespace WPFluent.Controls;
+
+/// <summary>
+/// Simple Card with content and <see cref="Footer"/>.
+/// </summary>
+public class Card : System.Windows.Controls.ContentControl
+{
+    /// <summary>
+    /// Identifies the <see cref="Footer"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty FooterProperty = DependencyProperty.Register(
+        nameof(Footer),
+        typeof(object),
+        typeof(Card),
+        new PropertyMetadata(null, OnFooterChanged));
+
+    /// <summary>
+    /// Identifies the <see cref="HasFooter"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty HasFooterProperty = DependencyProperty.Register(
+        nameof(HasFooter),
+        typeof(bool),
+        typeof(Card),
+        new PropertyMetadata(false));
+
+    private static void OnFooterChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+    {
+        if(d is not Card control)
+        {
+            return;
+        }
+
+        control.SetValue(HasFooterProperty, control.Footer != null);
+    }
+
+    /// <summary>
+    /// Gets or sets additional content displayed at the bottom.
+    /// </summary>
+    public object? Footer { get => GetValue(FooterProperty); set => SetValue(FooterProperty, value); }
+
+    /// <summary>
+    /// Gets a value indicating whether the <see cref="Card"/> has a <see cref="Footer"/>.
+    /// </summary>
+    public bool HasFooter
+    {
+        get => (bool)GetValue(HasFooterProperty);
+        internal set => SetValue(HasFooterProperty, value);
+    }
+}