优化更新代码，添加界面功能并整合

WPFluent/Services/SnackbarService.cs

@@ -0,0 +1,44 @@
+
+
+
+using WPFluent.Controls;
+
+namespace WPFluent;
+
+/// <summary>
+/// A service that provides methods related to displaying the <see cref="Snackbar"/>.
+/// </summary>
+public class SnackbarService : ISnackbarService
+{
+    private SnackbarPresenter? _presenter;
+
+    private Snackbar? _snackbar;
+
+    /// <inheritdoc/>
+    public SnackbarPresenter? GetSnackbarPresenter() { return _presenter; }
+
+    /// <inheritdoc/>
+    public void SetSnackbarPresenter(SnackbarPresenter contentPresenter) { _presenter = contentPresenter; }
+
+    /// <inheritdoc/>
+    public void Show(string title, string message, ControlAppearance appearance, IconElement? icon, TimeSpan timeout)
+    {
+        if(_presenter is null)
+        {
+            throw new InvalidOperationException($"The SnackbarPresenter was never set");
+        }
+
+        _snackbar ??= new Snackbar(_presenter);
+
+        _snackbar.SetCurrentValue(Snackbar.TitleProperty, title);
+        _snackbar.SetCurrentValue(System.Windows.Controls.ContentControl.ContentProperty, message);
+        _snackbar.SetCurrentValue(Snackbar.AppearanceProperty, appearance);
+        _snackbar.SetCurrentValue(Snackbar.IconProperty, icon);
+        _snackbar.SetCurrentValue(Snackbar.TimeoutProperty, timeout.TotalSeconds == 0 ? DefaultTimeOut : timeout);
+
+        _snackbar.Show(true);
+    }
+
+    /// <inheritdoc/>
+    public TimeSpan DefaultTimeOut { get; set; } = TimeSpan.FromSeconds(5);
+}