Windows message loop manager (#9614)

src/Core/src/Handlers/Window/WindowHandler.Windows.cs

@@ -1,5 +1,6 @@
 using System;
 using Microsoft.UI.Xaml.Controls;
+using Microsoft.Maui.ApplicationModel;
 
 namespace Microsoft.Maui.Handlers
 {

src/Core/src/Hosting/EssentialsMauiAppBuilderExtensions.cs

@@ -62,10 +62,6 @@ internal static MauiAppBuilder UseEssentials(this MauiAppBuilder builder)
  }));
 #elif WINDOWS
  life.AddWindows(windows => windows
- .OnPlatformMessage((window, args) =>
- {
- ApplicationModel.Platform.OnWindowMessage(args.Hwnd, args.MessageId, args.WParam, args.LParam);
- })
  .OnActivated((window, args) =>
  {
  ApplicationModel.Platform.OnActivated(window, args);

src/Core/src/Platform/Windows/MauiWinUIWindow.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Runtime.InteropServices;
+using Microsoft.Maui.ApplicationModel;
 using Microsoft.Maui.Devices;
 using Microsoft.Maui.LifecycleEvents;
 using Microsoft.UI;
@@ -10,11 +11,15 @@ namespace Microsoft.Maui
 {
  public class MauiWinUIWindow : UI.Xaml.Window
  {
+ readonly WindowMessageManager _windowManager;
+
  IntPtr _windowIcon;
  bool _enableResumeEvent;
 
  public MauiWinUIWindow()
  {
+ _windowManager = WindowMessageManager.Get(this);
+
  Activated += OnActivated;
  Closed += OnClosedPrivate;
  VisibilityChanged += OnVisibilityChanged;
@@ -62,58 +67,37 @@ protected virtual void OnVisibilityChanged(object sender, UI.Xaml.WindowVisibili
  MauiWinUIApplication.Current.Services?.InvokeLifecycleEvents<WindowsLifecycle.OnVisibilityChanged>(del => del(this, args));
  }
 
- #region Platform Window
-
- IntPtr _hwnd = IntPtr.Zero;
-
- /// <summary>
- /// Returns a pointer to the underlying platform window handle (hWnd).
- /// </summary>
- public IntPtr WindowHandle
- {
- get
- {
- if (_hwnd == IntPtr.Zero)
- _hwnd = this.GetWindowHandle();
- return _hwnd;
- }
- }
-
- PlatformMethods.WindowProc? newWndProc = null;
- IntPtr oldWndProc = IntPtr.Zero;
+ public IntPtr WindowHandle => _windowManager.WindowHandle;
 
  void SubClassingWin32()
  {
  MauiWinUIApplication.Current.Services?.InvokeLifecycleEvents<WindowsLifecycle.OnPlatformWindowSubclassed>(
  del => del(this, new WindowsPlatformWindowSubclassedEventArgs(WindowHandle)));
 
- newWndProc = new PlatformMethods.WindowProc(NewWindowProc);
- oldWndProc = PlatformMethods.SetWindowLongPtr(WindowHandle, PlatformMethods.WindowLongFlags.GWL_WNDPROC, newWndProc);
+ _windowManager.WindowMessage += OnWindowMessage;
 
- IntPtr NewWindowProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam)
+ void OnWindowMessage(object? sender, WindowMessageEventArgs e)
  {
- if (msg == WindowsPlatformMessageIds.WM_SETTINGCHANGE || msg == WindowsPlatformMessageIds.WM_THEMECHANGE)
+ if (e.MessageId == PlatformMethods.MessageIds.WM_SETTINGCHANGE ||
+ e.MessageId == PlatformMethods.MessageIds.WM_THEMECHANGE)
+ {
  MauiWinUIApplication.Current.Application?.ThemeChanged();
-
- if (msg == WindowsPlatformMessageIds.WM_DPICHANGED)
+ }
+ else if (e.MessageId == PlatformMethods.MessageIds.WM_DPICHANGED)
  {
- var dpiX = (short)(long)wParam;
- var dpiY = (short)((long)wParam >> 16);
+ var dpiX = (short)(long)e.WParam;
+ var dpiY = (short)((long)e.WParam >> 16);
 
  var window = this.GetWindow();
  if (window is not null)
  window.DisplayDensityChanged(dpiX / DeviceDisplay.BaseLogicalDpi);
  }
 
  MauiWinUIApplication.Current.Services?.InvokeLifecycleEvents<WindowsLifecycle.OnPlatformMessage>(
- m => m.Invoke(this, new WindowsPlatformMessageEventArgs(hWnd, msg, wParam, lParam)));
-
- return PlatformMethods.CallWindowProc(oldWndProc, hWnd, msg, wParam, lParam);
+ m => m.Invoke(this, new WindowsPlatformMessageEventArgs(e.Hwnd, e.MessageId, e.WParam, e.LParam)));
  }
  }
 
- #endregion
-
  /// <summary>
  /// Default the Window Icon to the icon stored in the .exe, if any.
  /// 

src/Core/src/Platform/Windows/NavigationRootManager.cs

@@ -1,4 +1,5 @@
 using System;
+using Microsoft.Maui.ApplicationModel;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
 using Microsoft.UI.Xaml.Media;

src/Core/src/Platform/Windows/WindowExtensions.cs

@@ -1,4 +1,5 @@
 using System;
+using Microsoft.Maui.ApplicationModel;
 using Microsoft.Maui.Devices;
 using System.Threading.Tasks;
 using Microsoft.Maui.Media;

src/Essentials/src/AppInfo/AppInfo.uwp.cs

@@ -1,13 +1,9 @@
 using System;
-using System.Globalization;
-using Windows.ApplicationModel;
 using System.Diagnostics;
+using System.Globalization;
 using System.Reflection;
-#if WINDOWS
 using Microsoft.UI.Xaml;
-#else
-using Windows.UI.Xaml;
-#endif
+using Windows.ApplicationModel;
 
 namespace Microsoft.Maui.ApplicationModel
 {
@@ -19,11 +15,13 @@ class AppInfoImplementation : IAppInfo
 
  ApplicationTheme? _applicationTheme;
 
+ readonly ActiveWindowTracker _activeWindowTracker;
+
  public AppInfoImplementation()
  {
- // TODO: NET7 use new public events
- if (WindowStateManager.Default is WindowStateManagerImplementation impl)
-  impl.ActiveWindowThemeChanged += OnActiveWindowThemeChanged;
+ _activeWindowTracker = new(WindowStateManager.Default);
+ _activeWindowTracker.Start();
+ _activeWindowTracker.WindowMessage += OnWindowMessage;
 
  if (MainThread.IsMainThread)
  OnActiveWindowThemeChanged();
@@ -78,7 +76,14 @@ public AppTheme RequestedTheme
  public LayoutDirection RequestedLayoutDirection =>
  CultureInfo.CurrentCulture.TextInfo.IsRightToLeft ? LayoutDirection.RightToLeft : LayoutDirection.LeftToRight;
 
- void OnActiveWindowThemeChanged(object sender = null, EventArgs e = null)
+ void OnWindowMessage(object sender, WindowMessageEventArgs e)
+ {
+ if (e.MessageId == PlatformMethods.MessageIds.WM_SETTINGCHANGE ||
+ e.MessageId == PlatformMethods.MessageIds.WM_THEMECHANGE)
+ OnActiveWindowThemeChanged();
+ }
+
+ void OnActiveWindowThemeChanged()
  {
  if (Application.Current is Application app)
  _applicationTheme = app.RequestedTheme;

src/Essentials/src/DeviceDisplay/DeviceDisplay.uwp.cs

@@ -11,8 +11,16 @@ namespace Microsoft.Maui.Devices
  partial class DeviceDisplayImplementation
  {
  readonly object locker = new object();
+ readonly ActiveWindowTracker _activeWindowTracker;
+
  DisplayRequest? displayRequest;
 
+ public DeviceDisplayImplementation()
+ {
+ _activeWindowTracker = new(WindowStateManager.Default);
+ _activeWindowTracker.WindowMessage += OnWindowMessage;
+ }
+
  protected override bool GetKeepScreenOn()
  {
  lock (locker)
@@ -44,8 +52,6 @@ protected override void SetKeepScreenOn(bool keepScreenOn)
  }
  }
 
- AppWindow? _currentAppWindowListeningTo;
-
  protected override DisplayInfo GetMainDisplayInfo()
  {
  if (WindowStateManager.Default.GetActiveAppWindow(false) is not AppWindow appWindow)
@@ -102,47 +108,22 @@ protected override DisplayInfo GetMainDisplayInfo()
  return null;
  }
 
- protected override void StartScreenMetricsListeners()
- {
- MainThread.BeginInvokeOnMainThread(() =>
- {
- WindowStateManager.Default.ActiveWindowDisplayChanged += OnWindowDisplayChanged;
- WindowStateManager.Default.ActiveWindowChanged += OnCurrentWindowChanged;
+ protected override void StartScreenMetricsListeners() =>
+ MainThread.BeginInvokeOnMainThread(_activeWindowTracker.Start);
 
- _currentAppWindowListeningTo = WindowStateManager.Default.GetActiveAppWindow(true)!;
- _currentAppWindowListeningTo.Changed += OnAppWindowChanged;
- });
- }
+ protected override void StopScreenMetricsListeners() =>
+ MainThread.BeginInvokeOnMainThread(_activeWindowTracker.Stop);
 
- protected override void StopScreenMetricsListeners()
+ // Currently there isn't a way to detect Orientation Changes unless you subclass the WinUI.Window and watch the messages.
+ // This is the "subtlest" way to currently wire this together.
+ // Hopefully there will be a more public API for this down the road so we can just use that directly from Essentials
+ void OnWindowMessage(object? sender, WindowMessageEventArgs e)
  {
- MainThread.BeginInvokeOnMainThread(() =>
- {
- WindowStateManager.Default.ActiveWindowChanged -= OnCurrentWindowChanged;
- WindowStateManager.Default.ActiveWindowDisplayChanged -= OnWindowDisplayChanged;
-
- if (_currentAppWindowListeningTo != null)
- _currentAppWindowListeningTo.Changed -= OnAppWindowChanged;
-
- _currentAppWindowListeningTo = null;
- });
- }
-
- void OnCurrentWindowChanged(object? sender, EventArgs e)
- {
- if (_currentAppWindowListeningTo != null)
- _currentAppWindowListeningTo.Changed -= OnAppWindowChanged;
-
- _currentAppWindowListeningTo = WindowStateManager.Default.GetActiveAppWindow(true)!;
- _currentAppWindowListeningTo.Changed += OnAppWindowChanged;
+ if (e.MessageId == PlatformMethods.MessageIds.WM_DISPLAYCHANGE ||
+ e.MessageId == PlatformMethods.MessageIds.WM_DPICHANGED)
+ OnMainDisplayInfoChanged();
  }
 
- void OnWindowDisplayChanged(object? sender, EventArgs e) =>
- OnMainDisplayInfoChanged();
-
- void OnAppWindowChanged(AppWindow sender, AppWindowChangedEventArgs args) =>
- OnMainDisplayInfoChanged();
-
  static DisplayRotation CalculateRotation(DisplayOrientations orientation) =>
  orientation switch
  {

src/Essentials/src/Platform/ActiveWindowTracker.uwp.cs

@@ -0,0 +1,58 @@
+#nullable enable
+using System;
+
+namespace Microsoft.Maui.ApplicationModel
+{
+ class ActiveWindowTracker
+ {
+ readonly IWindowStateManager _windowStateManager;
+
+ WindowMessageManager? _currentWindowManager;
+
+ public ActiveWindowTracker(IWindowStateManager windowStateManager)
+ {
+ _windowStateManager = windowStateManager;
+ }
+
+ public event EventHandler<WindowMessageEventArgs>? WindowMessage;
+
+ public void Start()
+ {
+ var window = _windowStateManager.GetActiveWindow();
+ OnActiveWindowChanged(window);
+
+ _windowStateManager.ActiveWindowChanged += OnActiveWindowChanged;
+ }
+
+ public void Stop()
+ {
+ OnActiveWindowChanged(null);
+
+ _windowStateManager.ActiveWindowChanged -= OnActiveWindowChanged;
+ }
+
+ void OnActiveWindowChanged(object? sender, EventArgs e)
+ {
+ var window = _windowStateManager?.GetActiveWindow();
+ OnActiveWindowChanged(window);
+ }
+
+ void OnActiveWindowChanged(UI.Xaml.Window? window)
+ {
+ if (_currentWindowManager is not null)
+ {
+ _currentWindowManager.WindowMessage -= OnWindowMessage;
+ _currentWindowManager = null;
+ }
+
+ if (window is not null)
+ {
+ _currentWindowManager = WindowMessageManager.Get(window);
+ _currentWindowManager.WindowMessage += OnWindowMessage;
+ }
+ }
+
+ void OnWindowMessage(object? sender, WindowMessageEventArgs e) =>
+ WindowMessage?.Invoke(sender, e);
+ }
+}

src/Essentials/src/Platform/Platform.shared.cs

@@ -82,9 +82,6 @@ public static void OnLaunched(UI.Xaml.LaunchActivatedEventArgs e) =>
  public static void OnActivated(UI.Xaml.Window window, UI.Xaml.WindowActivatedEventArgs args) =>
  WindowStateManager.Default.OnActivated(window, args);
 
- public static void OnWindowMessage(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam) =>
- WindowStateManager.Default.OnWindowMessage(hWnd, msg, wParam, lParam);
-
 #elif TIZEN
  public static Tizen.Applications.Package CurrentPackage
  {