feat: support getting the current IDialogService from a Singleton

src/Maui/Prism.Maui/Common/MvvmHelpers.cs

@@ -1,5 +1,6 @@
-using System.ComponentModel;
+using System.ComponentModel;
 using System.Reflection;
+using Prism.Dialogs;
 using Prism.Navigation;
 using Prism.Navigation.Regions;
 using Prism.Navigation.Xaml;
@@ -272,27 +273,44 @@ public static void SetCurrentPageDelegate(Func<Page, Page> getCurrentPageDelegat
         return EvaluateCurrentPage(page);
     };
 
-    private static Page EvaluateCurrentPage(Page target)
+    private static Page GetTarget(Page target)
     {
-        Page child = null;
+        return target switch
+        {
+            FlyoutPage flyout => GetTarget(flyout.Detail),
+            TabbedPage tabbed => GetTarget(tabbed.CurrentPage),
+            NavigationPage navigation => GetTarget(navigation.CurrentPage),
+            ContentPage page => page,
+            _ => throw new NotSupportedException($"The page type '{target.GetType().FullName}' is not supported.")
+        };
+    }
 
-        if (target is FlyoutPage flyout)
-            child = flyout.Detail;
-        else if (target is TabbedPage tabbed)
-            child = tabbed.CurrentPage;
-        else if (target is NavigationPage np)
-            child = np.Navigation.NavigationStack.Last();
+    private static Page EvaluateCurrentPage(Page target)
+    {
+        Page child = GetTarget(target);
 
-        if (child != null)
+        if (child is not null)
             target = GetOnNavigatedToTargetFromChild(child);
 
         if (target is Page page)
+        {
+            if (target is IDialogContainer)
+            {
+                if (page.Parent is Page parentPage)
+                {
+                    return GetTarget(parentPage);
+                }
+
+                throw new InvalidOperationException("Unable to determine the current page.");
+            }
+
             return page.Parent switch
             {
                 TabbedPage tab when tab.CurrentPage != target => EvaluateCurrentPage(tab.CurrentPage),
                 NavigationPage nav when nav.CurrentPage != target => EvaluateCurrentPage(nav.CurrentPage),
                 _ => target
             };
+        }
 
         return null;
     }

src/Maui/Prism.Maui/Navigation/IWindowManager.cs

@@ -1,10 +1,33 @@
-using System;
 namespace Prism.Navigation;
 
+#nullable enable
+/// <summary>
+/// Defines an interface for managing windows within an application.
+/// </summary>
 public interface IWindowManager
 {
+    /// <summary>
+    /// Gets a read-only collection of all currently open windows.
+    /// </summary>
     IReadOnlyList<Window> Windows { get; }
 
+    /// <summary>
+    /// Gets the currently active window, if any.
+    /// </summary>
+    Window? Current { get; }
+
+    /// <summary>
+    /// Opens a new window.
+    /// </summary>
+    /// <param name="window">The Window object to be opened.</param>
+    /// <exception cref="ArgumentNullException">Thrown if the window parameter is null.</exception>
     void OpenWindow(Window window);
+
+    /// <summary>
+    /// Closes a specified window.
+    /// </summary>
+    /// <param name="window">The Window object to be closed.</param>
+    /// <exception cref="ArgumentNullException">Thrown if the window parameter is null.</exception>
     void CloseWindow(Window window);
 }
+

src/Maui/Prism.Maui/Navigation/IWindowManagerExtensions.cs

@@ -1,4 +1,7 @@
-namespace Prism.Navigation;
+using Prism.Dialogs;
+using Prism.Navigation.Xaml;
+
+namespace Prism.Navigation;
 
 /// <summary>
 /// Provides extensions for the <see cref="IWindowManager"/>
@@ -12,11 +15,32 @@ public static class IWindowManagerExtensions
     /// <returns>The <see cref="INavigationService"/> for the current <see cref="Page"/>.</returns>
     public static INavigationService GetCurrentNavigationService(this IWindowManager windowManager)
     {
-        var window = windowManager.Windows.OfType<PrismWindow>().First();
+        var page = windowManager.GetCurrentPage();
+        return Xaml.Navigation.GetNavigationService(page);
+    }
 
-        if (window.CurrentPage is null)
-            throw new InvalidOperationException("No current page has been set.");
+    /// <summary>
+    /// Gets the <see cref="IDialogService"/> for the currently displayed <see cref="Page"/>.
+    /// </summary>
+    /// <param name="windowManager">The <see cref="IWindowManager"/>.</param>
+    /// <returns>The <see cref="IDialogService"/> for the current <see cref="Page"/>.</returns>
+    public static IDialogService GetCurrentDialogService(this IWindowManager windowManager)
+    {
+        var page = windowManager.GetCurrentPage();
+        var container = page.GetContainerProvider();
+        return container.Resolve<IDialogService>();
+    }
 
-        return Xaml.Navigation.GetNavigationService(window.CurrentPage);
+    private static Page GetCurrentPage(this IWindowManager windowManager)
+    {
+        var window = windowManager.Current;
+        if (window is null)
+            throw new InvalidOperationException("No Window has been set in the Application");
+        else if (window is not PrismWindow prismWindow)
+            throw new InvalidOperationException($"Prism applications only support the use of PrismWindow, but found '{window.GetType().FullName}'.");
+        else if (prismWindow.CurrentPage is null)
+            throw new InvalidOperationException("No current page has been set.");
+        else
+            return prismWindow.CurrentPage;
     }
 }

src/Maui/Prism.Maui/Navigation/PrismWindow.cs

@@ -20,7 +20,7 @@ public PrismWindow(string name = DefaultWindowName)
 
     public string Name { get; }
 
-    public bool IsActive { get; private set; }
+    public bool IsActive { get; internal set; }
 
     internal Page CurrentPage => Page is null ? null : MvvmHelpers.GetCurrentPage(Page);
 

src/Maui/Prism.Maui/Navigation/PrismWindowManager.cs

@@ -1,4 +1,7 @@
-namespace Prism.Navigation;
+using Prism.Behaviors;
+using Prism.Extensions;
+
+namespace Prism.Navigation;
 
 internal sealed class PrismWindowManager : IWindowCreator, IWindowManager
 {
@@ -11,6 +14,9 @@ public PrismWindowManager(IApplication application)
 
     private Window _initialWindow;
 
+    private Window _current;
+    public Window Current => _current ?? _initialWindow;
+
     public IReadOnlyList<Window> Windows => _application.Windows.OfType<Window>().ToList();
 
     public Window CreateWindow(Application app, IActivationState activationState)
@@ -31,6 +37,11 @@ public void OpenWindow(Window window)
             _initialWindow = window;
         else
             _application.OpenWindow(window);
+
+        foreach(var pWindow in Windows.OfType<PrismWindow>().Where(x => x.IsActive))
+        {
+            pWindow.IsActive = window.Equals(pWindow);
+        }
     }
 
     public void CloseWindow(Window window)