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);
+        }
+    }
+}

src/common/Themes/Themes.vcxproj

@@ -31,10 +31,14 @@
   </ItemDefinitionGroup>
   <ItemGroup>
     <ClInclude Include="icon_helpers.h" />
+    <ClInclude Include="theme_listener.h" />
+    <ClInclude Include="theme_helpers.h" />
     <ClInclude Include="windows_colors.h" />
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="icon_helpers.cpp" />
+    <ClCompile Include="theme_listener.cpp" />
+    <ClCompile Include="theme_helpers.cpp" />
     <ClCompile Include="windows_colors.cpp" />
   </ItemGroup>
   <ItemGroup>

src/common/Themes/theme_helpers.cpp

@@ -0,0 +1,43 @@
+// Port Based on https://stackoverflow.com/a/62811758/5001796
+#include "theme_helpers.h"
+#include "dwmapi.h"
+#include <windows.h>
+#include <vector>
+
+#define DWMWA_USE_IMMERSIVE_DARK_MODE 20
+#define HKEY_WINDOWS_THEME L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize"
+
+// based on https://stackoverflow.com/questions/51334674/how-to-detect-windows-10-light-dark-mode-in-win32-application
+AppTheme ThemeHelpers::GetAppTheme()
+{
+    // The value is expected to be a REG_DWORD, which is a signed 32-bit little-endian
+    auto buffer = std::vector<char>(4);
+    auto cbData = static_cast<DWORD>(buffer.size() * sizeof(char));
+    auto res = RegGetValueW(
+        HKEY_CURRENT_USER,
+        HKEY_WINDOWS_THEME,
+        L"AppsUseLightTheme",
+        RRF_RT_REG_DWORD, // expected value type
+        nullptr,
+        buffer.data(),
+        &cbData);
+
+    if (res != ERROR_SUCCESS)
+    {
+        return AppTheme::Light;
+    }
+
+    // convert bytes written to our buffer to an int, assuming little-endian
+    auto i = int(buffer[3] << 24 |
+                 buffer[2] << 16 |
+                 buffer[1] << 8 |
+                 buffer[0]);
+
+    return AppTheme(i);
+}
+
+void ThemeHelpers::SetImmersiveDarkMode(HWND window, bool enabled)
+{
+    int useImmersiveDarkMode = enabled ? 1 : 0;
+    DwmSetWindowAttribute(window, DWMWA_USE_IMMERSIVE_DARK_MODE, &useImmersiveDarkMode, sizeof(useImmersiveDarkMode));
+}

src/common/Themes/theme_helpers.h

@@ -0,0 +1,14 @@
+#pragma once
+#include <windows.h>
+
+enum class AppTheme
+{
+    Dark = 0,
+    Light = 1
+};
+
+struct ThemeHelpers
+{
+    static AppTheme GetAppTheme();
+    static void ThemeHelpers::SetImmersiveDarkMode(HWND window, bool enabled);
+};

src/common/Themes/theme_listener.cpp

@@ -0,0 +1,57 @@
+#include "theme_listener.h"
+
+#define HKEY_WINDOWS_THEME L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize"
+
+DWORD WINAPI _checkTheme(LPVOID lpParam)
+{
+    auto listener = (ThemeListener*)lpParam;
+    listener->CheckTheme();
+    return 0;
+}
+
+void ThemeListener::AddChangedHandler(THEME_HANDLE handle)
+{
+    handles.push_back(handle);
+}
+
+void ThemeListener::DelChangedHandler(THEME_HANDLE handle)
+{
+    auto it = std::find(handles.begin(), handles.end(), handle);
+    handles.erase(it);
+}
+
+void ThemeListener::CheckTheme()
+{
+    HANDLE hEvent;
+    HKEY hKey;
+
+    // Open the Key to listen
+    RegOpenKeyEx(HKEY_CURRENT_USER, HKEY_WINDOWS_THEME, 0, KEY_NOTIFY, &hKey);
+
+    while (true)
+    {
+        // Create an event.
+        hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
+        if (hEvent != 0)
+        {
+            // Watch the registry key for a change of value.
+            RegNotifyChangeKeyValue(hKey,
+                                    TRUE,
+                                    REG_NOTIFY_CHANGE_LAST_SET,
+                                    hEvent,
+                                    TRUE);
+
+            WaitForSingleObject(hEvent, INFINITE);
+
+            auto _theme = ThemeHelpers::GetAppTheme();
+            if (AppTheme != _theme)
+            {
+                AppTheme = _theme;
+                for (int i = 0; i < handles.size(); i++)
+                {
+                    handles[i]();
+                }
+            }
+        }
+    }
+}

src/common/Themes/theme_listener.h

@@ -0,0 +1,34 @@
+#include "theme_helpers.h"
+#include "dwmapi.h"
+#include <windows.h>
+#include <iostream>
+#include <vector>
+
+typedef void (*THEME_HANDLE)();
+DWORD WINAPI _checkTheme(LPVOID lpParam);
+
+#pragma once
+class ThemeListener
+{
+public:
+    ThemeListener()
+    {
+        AppTheme = ThemeHelpers::GetAppTheme();
+        dwThreadHandle = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)_checkTheme, this, 0, &dwThreadId);
+    }
+    ~ThemeListener()
+    {
+        CloseHandle(dwThreadHandle);
+        dwThreadId = 0;
+    }
+
+    AppTheme AppTheme;
+    void ThemeListener::AddChangedHandler(THEME_HANDLE handle);
+    void ThemeListener::DelChangedHandler(THEME_HANDLE handle);
+    void CheckTheme();
+
+private:
+    HANDLE dwThreadHandle;
+    DWORD dwThreadId;
+    std::vector<THEME_HANDLE> handles;
+};

src/common/Themes/windows_colors.cpp

@@ -1,4 +1,5 @@
 #include "windows_colors.h"
+#include "theme_helpers.h"
 
 DWORD WindowsColors::rgb_color(DWORD abgr_color)
 {
@@ -65,7 +66,7 @@ WindowsColors::Color WindowsColors::get_background_color()
 
 bool WindowsColors::is_dark_mode()
 {
-    return rgb_color(get_background_color()) == 0;
+    return ThemeHelpers::GetAppTheme() == AppTheme::Dark;
 }
 
 bool WindowsColors::update()