Added support for switching to Accent background color if the user requests this via Windows theme settings

src/TheXamlGuy.NotificationFlyout.Shared.UI/Helpers/SystemPersonalisationHelper.cs

@@ -7,6 +7,8 @@ namespace TheXamlGuy.NotificationFlyout.Shared.UI.Helpers
 {
     public class SystemPersonalisationHelper : IWndProcHandler
     {
+        private static readonly Lazy<SystemPersonalisationHelper> _current = new(() => new SystemPersonalisationHelper());
+
         private readonly UISettings _settings = new();
         private readonly string PersonalizeKey = @"Software\Microsoft\Windows\CurrentVersion\Themes\Personalize";
         private SystemTheme _currentTheme;
@@ -22,10 +24,17 @@ namespace TheXamlGuy.NotificationFlyout.Shared.UI.Helpers
 
         public event EventHandler<SystemPersonalisationChangedEventArgs> ThemeChanged;
 
+        public static SystemPersonalisationHelper Current => _current.Value;
         public bool IsColorPrevalence => GetIsColorPrevalence();
         public SystemTheme Theme => GetTheme();
 
-        public static SystemPersonalisationHelper Create() => new();
+        public void Handle(uint message, IntPtr wParam, IntPtr lParam)
+        {
+            if (message == (int)WndProcMessages.WM_SETTINGCHANGE)
+            {
+                RaiseThemeChangedEvent();
+            }
+        }
 
         private bool GetIsColorPrevalence()
         {
@@ -53,13 +62,5 @@ namespace TheXamlGuy.NotificationFlyout.Shared.UI.Helpers
                 ThemeChanged?.Invoke(this, new SystemPersonalisationChangedEventArgs(theme, isColorPrevalence));
             }
         }
-
-        public void Handle(uint message, IntPtr wParam, IntPtr lParam)
-        {
-            if (message == (int)WndProcMessages.WM_SETTINGCHANGE)
-            {
-                RaiseThemeChangedEvent();
-            }
-        }
     }
 }

src/TheXamlGuy.NotificationFlyout.Uwp.UI.Controls/NotificationFlyoutPresenter/NotificationFlyoutPresenter.cs

@@ -1,9 +1,25 @@
-using Windows.UI.Xaml.Controls;
+using TheXamlGuy.NotificationFlyout.Shared.UI.Helpers;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
 
 namespace TheXamlGuy.NotificationFlyout.Uwp.UI.Controls
 {
     public class NotificationFlyoutPresenter : ContentControl
     {
-        public NotificationFlyoutPresenter() => DefaultStyleKey = typeof(NotificationFlyoutPresenter);
+        private SystemPersonalisationHelper _systemPersonalisationHelper;
+
+        public NotificationFlyoutPresenter()
+        {
+            DefaultStyleKey = typeof(NotificationFlyoutPresenter);
+
+            _systemPersonalisationHelper = SystemPersonalisationHelper.Current;
+            _systemPersonalisationHelper.ThemeChanged += OnThemeChanged;
+        }
+
+        protected override void OnApplyTemplate() => UpdateThemeVisualStates(false);
+
+        private void OnThemeChanged(object sender, SystemPersonalisationChangedEventArgs args) => UpdateThemeVisualStates(true);
+
+        private void UpdateThemeVisualStates(bool useTransition) => VisualStateManager.GoToState(this, _systemPersonalisationHelper.IsColorPrevalence ? "ColorPrevalenceTheme" : "DefaultTheme", useTransition);
     }
 }

src/TheXamlGuy.NotificationFlyout.Wpf.UI.Controls/NotificationFlyout/NotificationFlyoutXamlHost.cs

@@ -145,7 +145,7 @@ namespace TheXamlGuy.NotificationFlyout.Wpf.UI.Controls
             _notificationIconHelper = NotificationIconHelper.Create();
             _notificationIconHelper.IconInvoked += OnIconInvoked;
 
-            _systemPersonalisationHelper = SystemPersonalisationHelper.Create();
+            _systemPersonalisationHelper = SystemPersonalisationHelper.Current;
             _systemPersonalisationHelper.ThemeChanged += OnThemeChanged;
 
             UpdateIcons();