Fix: failing to correctly trigger the methods of the INavigationAware…

… interface. (#1177)

* fix: failing to correctly trigger the methods of the INavigationAware interface.

when both the View and ViewModel inherit from the INavigationAware interface, only the OnNavigatedToAsync/OnNavigatedFromAsync methods of the View are triggered

* refactor: reduce code duplication.

src/Wpf.Ui/Controls/NavigationView/NavigationViewContentPresenter.cs

@@ -184,33 +184,42 @@ private void ApplyTransitionEffectToNavigatedPage(object content)
 
     private static void NotifyContentAboutNavigatingTo(object content)
     {
-        switch (content)
-        {
-            case INavigationAware navigationAwareNavigationContent:
-                _ = Task.Run(navigationAwareNavigationContent.OnNavigatedToAsync).ConfigureAwait(false);
-                break;
-            case INavigableView<object> { ViewModel: INavigationAware navigationAwareNavigableViewViewModel }:
-                _ = Task.Run(navigationAwareNavigableViewViewModel.OnNavigatedToAsync).ConfigureAwait(false);
-                break;
-            case FrameworkElement { DataContext: INavigationAware navigationAwareCurrentContent }:
-                _ = Task.Run(navigationAwareCurrentContent.OnNavigatedToAsync).ConfigureAwait(false);
-                break;
-        }
+        NotifyContentAboutNavigating(content, navigationAware => navigationAware.OnNavigatedToAsync());
     }
 
     private static void NotifyContentAboutNavigatingFrom(object content)
+    {
+        NotifyContentAboutNavigating(content, navigationAware => navigationAware.OnNavigatedFromAsync());
+    }
+
+    [System.Diagnostics.CodeAnalysis.SuppressMessage(
+        "ReSharper",
+        "SuspiciousTypeConversion.Global",
+        Justification = "The library user might make a class inherit from both FrameworkElement and INavigationAware at the same time."
+    )]
+    private static void NotifyContentAboutNavigating(object content, Func<INavigationAware, Task> function)
     {
         switch (content)
         {
+            // The order in which the OnNavigatedToAsync/OnNavigatedFromAsync methods of View and ViewModel are called
+            // is not guaranteed
             case INavigationAware navigationAwareNavigationContent:
-                _ = Task.Run(navigationAwareNavigationContent.OnNavigatedFromAsync).ConfigureAwait(false);
+                _ = Task.Run(() => function(navigationAwareNavigationContent)).ConfigureAwait(false);
+                if (
+                    navigationAwareNavigationContent
+                        is FrameworkElement { DataContext: INavigationAware viewModel }
+                    && !ReferenceEquals(viewModel, navigationAwareNavigationContent)
+                )
+                {
+                    _ = Task.Run(() => function(viewModel)).ConfigureAwait(false);
+                }
+
                 break;
             case INavigableView<object> { ViewModel: INavigationAware navigationAwareNavigableViewViewModel }:
-                _ = Task.Run(navigationAwareNavigableViewViewModel.OnNavigatedFromAsync)
-                    .ConfigureAwait(false);
+                _ = Task.Run(() => function(navigationAwareNavigableViewViewModel)).ConfigureAwait(false);
                 break;
             case FrameworkElement { DataContext: INavigationAware navigationAwareCurrentContent }:
-                _ = Task.Run(navigationAwareCurrentContent.OnNavigatedFromAsync).ConfigureAwait(false);
+                _ = Task.Run(() => function(navigationAwareCurrentContent)).ConfigureAwait(false);
                 break;
         }
     }