Fixed stackoverflow...

NotificationFlyout.Tray/NotificationFlyout.Tray.csproj

@@ -7,6 +7,7 @@
     <AssetTargetFallback>uap10.0.19041</AssetTargetFallback>
     <Platforms>AnyCPU;x64</Platforms>
     <StartupObject>NotificationFlyout.Tray.Program</StartupObject>
+    <LangVersion>9.0</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>

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

@@ -1,4 +1,6 @@
-using Windows.UI.Xaml;
+using Windows.UI.Popups;
+using Windows.UI.ViewManagement;
+using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Controls.Primitives;
 
@@ -20,6 +22,14 @@ namespace NotificationFlyout.Uwp.UI.Controls
 
             _templateSettings = new NotificationFlyoutPresenterTemplateSettings();
             SetValue(TemplateSettingsProperty, _templateSettings);
+
+            UISettings uiSettings = new UISettings();
+            uiSettings.ColorValuesChanged += UiSettings_ColorValuesChanged;
+        }
+
+        private void UiSettings_ColorValuesChanged(UISettings sender, object args)
+        {
+            MessageDialog d = new MessageDialog("", "");
         }
 
         public NotificationFlyoutPresenterTemplateSettings TemplateSettings

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

@@ -80,6 +80,7 @@ namespace NotificationFlyout.Wpf.UI.Controls
 
         private NotificationFlyoutPresenter GetNotificationFlyoutPresenter()
         {
+            if (_host == null) return null;
             return _host.GetUwpInternalObject() as NotificationFlyoutPresenter;
         }
 
@@ -154,6 +155,8 @@ namespace NotificationFlyout.Wpf.UI.Controls
         private void UpdateWindow()
         {
             var flyoutPresenter = GetNotificationFlyoutPresenter();
+            if (flyoutPresenter == null) return;
+
             var taskbarState = _taskbarHelper.GetCurrentState();
 
             var screen = Screen.FromHandle(this.GetHandle());

NotificationFlyout.Wpf.UI/Extensions/RegistryKeyExtensions.cs

@@ -1,12 +0,0 @@
-using Microsoft.Win32;
-
-namespace NotificationFlyout.Wpf.UI.Extensions
-{
-    public static class RegistryKeyExtensions
-    {
-        public static T GetValue<T>(this RegistryKey self, string valueName, T defaultValue)
-        {
-            return self.GetValue(valueName, defaultValue) is T t ? t : defaultValue;
-        }
-    }
-}

NotificationFlyout.Wpf.UI/Helpers/NotificationIconHelper.cs

@@ -1,5 +1,4 @@
-using Microsoft.Windows.Sdk;
-using NotificationFlyout.Wpf.UI.Extensions;
+using NotificationFlyout.Wpf.UI.Extensions;
 using System;
 using System.Runtime.InteropServices;
 using System.Windows;
@@ -97,6 +96,9 @@ namespace NotificationFlyout.Wpf.UI.Helpers
             }
         }
 
+        [DllImport("user32.dll", SetLastError = true)]
+        private static extern IntPtr DefWindowProcW(IntPtr handle, uint msg, IntPtr wParam, IntPtr lParam);
+
         [DllImport("shell32.dll", SetLastError = true)]
         private static extern int Shell_NotifyIcon(NotifyIconCommand notifyCommand, ref NotifyIconData notifyIconData);
 
@@ -133,7 +135,6 @@ namespace NotificationFlyout.Wpf.UI.Helpers
         }
 
         private void RemoveNotificationIcon() => WriteNotifyIconData(NotifyIconCommand.Delete, NotifyIconDataMember.Message);
-
         private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
         {
             if (msg == CallbackMessage)
@@ -164,8 +165,8 @@ namespace NotificationFlyout.Wpf.UI.Helpers
                     IconInvoked?.Invoke(this, new NotificationIconInvokedEventArgs { MouseButton = mouseButton });
                 }
             }
- 
-            return (IntPtr)(int)PInvoke.DefWindowProc((HWND)hwnd, (uint)msg, (WPARAM)(UIntPtr)(uint)wParam, (LPARAM)lParam);
+
+            return DefWindowProcW(hwnd, (uint)msg, wParam, (lParam));
         }
 
         private void WriteNotifyIconData(NotifyIconCommand command, NotifyIconDataMember flags)

NotificationFlyout.Wpf.UI/Helpers/RegistryHelper.cs

@@ -0,0 +1,15 @@
+using Microsoft.Win32;
+
+namespace NotificationFlyout.Wpf.UI.Helpers
+{
+    internal static class RegistryHelper
+    {
+        public static TValue GetDwordValue<TValue>(string key, string valueName)
+        {
+            using var baseKey = RegistryKey.OpenBaseKey(RegistryHive.CurrentUser, RegistryView.Registry64);
+            using var subKey = baseKey.OpenSubKey(key);
+
+            return (TValue)subKey.GetValue(valueName, 0);
+        }
+    }
+}

NotificationFlyout.Wpf.UI/Helpers/SystemSettingsHelper.cs

@@ -1,30 +1,21 @@
-using Microsoft.Win32;
-using NotificationFlyout.Wpf.UI.Extensions;
+using NotificationFlyout.Wpf.UI.Extensions;
 using System;
 
 namespace NotificationFlyout.Wpf.UI.Helpers
 {
     public static class SystemSettingsHelper
     {
-        private static readonly string PersonalizeKey = @"Software\Microsoft\Windows\CurrentVersion\Themes\Personalize";
-
-        public static SystemTheme DefaultSystemTheme => GetDefaultSystemTheme();
+       public static SystemTheme DefaultSystemTheme => GetDefaultSystemTheme();
 
         private static SystemTheme GetDefaultSystemTheme()
         {
-            return Environment.OSVersion.IsGreaterThan(OperatingSystemVersion.Windows10_1809) &&
-                   ReadDword(PersonalizeKey, "SystemUsesLightTheme")
-                ? SystemTheme.Light
-                : SystemTheme.Dark;
+            return Environment.OSVersion.IsGreaterThan(OperatingSystemVersion.Windows10_1809) && DoesSystemUsesLightTheme() ? SystemTheme.Light : SystemTheme.Dark;
         }
 
-        private static bool ReadDword(string key, string valueName, int defaultValue = 0)
+        private static bool DoesSystemUsesLightTheme()
         {
-            using var baseKey = RegistryKey.OpenBaseKey(RegistryHive.CurrentUser, RegistryView.Registry64);
-            using var subKey = baseKey.OpenSubKey(key);
-            return subKey.GetValue<int>(valueName, defaultValue) > 0;
+            var personalizeKey = @"Software\Microsoft\Windows\CurrentVersion\Themes\Personalize";
+            return RegistryHelper.GetDwordValue<int>(personalizeKey, "SystemUsesLightTheme") > 0;
         }
-
-        public static bool IsTransparencyEnabled => ReadDword(PersonalizeKey, "EnableTransparency");
     }
 }

NotificationFlyout.Wpf.UI/Helpers/SystemTheme.cs

@@ -3,6 +3,6 @@
     public enum SystemTheme
     {
         Dark,
-        Light
+        Light,
     }
 }

NotificationFlyout.Wpf.UI/Helpers/TaskbarHelper.cs

@@ -72,11 +72,17 @@ namespace NotificationFlyout.Wpf.UI.Helpers
             return state;
         }
 
+        [DllImport("user32.dll", SetLastError = true)]
+        private static extern IntPtr DefWindowProcW(IntPtr handle, uint msg, IntPtr wParam, IntPtr lParam);
+
         private static IntPtr GetSystemTrayHandle()
         {
             return WindowHelper.GetHandle(ShellTrayHandleName);
         }
 
+        [DllImport("shell32.dll", SetLastError = true)]
+        private static extern IntPtr SHAppBarMessage(AppBarMessage dwMessage, ref AppBarData pData);
+
         private AppBarData GetAppBarData(IntPtr handle)
         {
             return new AppBarData
@@ -86,20 +92,6 @@ namespace NotificationFlyout.Wpf.UI.Helpers
             };
         }
 
-        [StructLayout(LayoutKind.Sequential)]
-        private struct AppBarData
-        {
-            public uint cbSize;
-            public IntPtr hWnd;
-            public uint uCallbackMessage;
-            public AppBarEdge uEdge;
-            public RECT rect;
-            public int lParam;
-        }
-
-        [DllImport("shell32.dll", SetLastError = true)]
-        private static extern IntPtr SHAppBarMessage(AppBarMessage dwMessage, ref AppBarData pData);
-
         private void GetAppBarPosition(ref AppBarData appBarData)
         {
             SHAppBarMessage(AppBarMessage.GetTaskbarPos, ref appBarData);
@@ -112,7 +104,18 @@ namespace NotificationFlyout.Wpf.UI.Helpers
                 TaskbarChanged?.Invoke(this, EventArgs.Empty);
             }
 
-            return (IntPtr)(int)PInvoke.DefWindowProc((HWND)hwnd, (uint)msg, (WPARAM)(UIntPtr)(uint)wParam, (LPARAM)lParam);
+            return DefWindowProcW(hwnd, (uint)msg, wParam, (lParam));
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        private struct AppBarData
+        {
+            public uint cbSize;
+            public IntPtr hWnd;
+            public uint uCallbackMessage;
+            public AppBarEdge uEdge;
+            public RECT rect;
+            public int lParam;
         }
     }
 }