Immersive dark mode + Theme Listener (#18315)

* C++ impl of immersive dark mode

* Stop using the hardcoded value.

* Conjured up theme listener based on registry.

* Update MainWindow.xaml.cpp

* Update expect.txt

* Moved themehelpers to the common themes lib.

* Ported theme helpers back to .NET

* Update expect.txt

* Updated C# Theme Listening logic to mimic the one from Windows Community Toolkit.

* Replaced unmanaged code for RegisterForImmersiveDarkMode with unmanaged ThemeListener class.

* Fix upstream changes

* Update ThemeListener.h

* Update ThemeListener.h

* Proper formatting

* Added handler to Keyboard Manager.

* Update EditKeyboardWindow.cpp

* Added dwmapi.lib to runner, removed condition from additional dependencies.

* Update PowerRenameUI.vcxproj

* Added new deps for ManagedCommon to Product.wxs

* Crude attempts and understanding installer

* Removed Microsoft.Win32.Registry.dll from product.wxs.

* Updated dictionary

* Renamed ThemeListener class file for consistency, removed unused CheckImmersiveDarkMode in theme_helpers.

* Update Themes.vcxproj

* Update theme_listener.cpp

* Removed SupportsImmersiveDarkMode version check

* Removed SupportsImmersiveDarkMode version check

* Whoops

* Update expect.txt

src/common/ManagedCommon/ManagedCommon.csproj

@@ -17,6 +17,8 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
+    <PackageReference Include="Microsoft.Win32.Registry" Version="5.0.0" />
+    <PackageReference Include="System.Management" Version="6.0.0" />
   </ItemGroup>
 
   <ItemGroup>

src/common/ManagedCommon/Theme.cs

@@ -14,4 +14,10 @@ namespace ManagedCommon
         HighContrastBlack,
         HighContrastWhite,
     }
+
+    public enum AppTheme
+    {
+        Dark = 0,
+        Light = 1,
+    }
 }

src/common/ManagedCommon/ThemeHelpers.cs

@@ -0,0 +1,37 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Linq;
+using System.Runtime.InteropServices;
+using Microsoft.Win32;
+
+namespace ManagedCommon
+{
+    // Based on https://stackoverflow.com/a/62811758/5001796
+    public static class ThemeHelpers
+    {
+        [DllImport("dwmapi.dll")]
+        private static extern int DwmSetWindowAttribute(IntPtr hwnd, int attr, ref int attrValue, int attrSize);
+
+        internal const string HKeyRoot = "HKEY_CURRENT_USER";
+        internal const string HkeyWindowsTheme = @"SOFTWARE\Microsoft\Windows\CurrentVersion\Themes";
+        internal const string HkeyWindowsPersonalizeTheme = $@"{HkeyWindowsTheme}\Personalize";
+        internal const string HValueAppTheme = "AppsUseLightTheme";
+        internal const int DWMWAImmersiveDarkMode = 20;
+
+        // based on https://stackoverflow.com/questions/51334674/how-to-detect-windows-10-light-dark-mode-in-win32-application
+        public static AppTheme GetAppTheme()
+        {
+            int value = (int)Registry.GetValue($"{HKeyRoot}\\{HkeyWindowsPersonalizeTheme}", HValueAppTheme, 1);
+            return (AppTheme)value;
+        }
+
+        public static void SetImmersiveDarkMode(IntPtr window, bool enabled)
+        {
+            int useImmersiveDarkMode = enabled ? 1 : 0;
+            _ = DwmSetWindowAttribute(window, DWMWAImmersiveDarkMode, ref useImmersiveDarkMode, sizeof(int));
+        }
+    }
+}

src/common/ManagedCommon/ThemeListener.cs

@@ -0,0 +1,62 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Management;
+using System.Security.Principal;
+
+namespace ManagedCommon
+{
+    /// <summary>
+    /// The Delegate for a ThemeChanged Event.
+    /// </summary>
+    /// <param name="sender">Sender ThemeListener</param>
+    public delegate void ThemeChangedEvent(ThemeListener sender);
+
+    public class ThemeListener : IDisposable
+    {
+        /// <summary>
+        /// Gets the App Theme.
+        /// </summary>
+        public AppTheme AppTheme { get; private set; }
+
+        /// <summary>
+        /// An event that fires if the Theme changes.
+        /// </summary>
+        public event ThemeChangedEvent ThemeChanged;
+
+        private readonly ManagementEventWatcher watcher;
+
+        public ThemeListener()
+        {
+            var currentUser = WindowsIdentity.GetCurrent();
+            var query = new WqlEventQuery(
+                $"SELECT * FROM RegistryValueChangeEvent WHERE Hive='HKEY_USERS' AND " +
+                $"KeyPath='{currentUser.User.Value}\\\\{ThemeHelpers.HkeyWindowsPersonalizeTheme.Replace("\\", "\\\\")}' AND ValueName='{ThemeHelpers.HValueAppTheme}'");
+            watcher = new ManagementEventWatcher(query);
+            watcher.EventArrived += Watcher_EventArrived;
+            watcher.Start();
+
+            AppTheme = ThemeHelpers.GetAppTheme();
+        }
+
+        private void Watcher_EventArrived(object sender, EventArrivedEventArgs e)
+        {
+            var appTheme = ThemeHelpers.GetAppTheme();
+
+            if (appTheme != AppTheme)
+            {
+                AppTheme = appTheme;
+
+                ThemeChanged?.Invoke(this);
+            }
+        }
+
+        public void Dispose()
+        {
+            watcher.Dispose();
+            GC.SuppressFinalize(this);
+        }
+    }
+}