add a managed native menu exporter for win32 tray icon menus.

src/Avalonia.Controls/ApiCompatBaseline.txt

@@ -37,6 +37,7 @@ MembersMustExist : Member 'public System.Action<Avalonia.Size> Avalonia.Controls
 MembersMustExist : Member 'public void Avalonia.Controls.Embedding.Offscreen.OffscreenTopLevelImplBase.Resized.set(System.Action<Avalonia.Size>)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public void Avalonia.Controls.Embedding.Offscreen.OffscreenTopLevelImplBase.SetCursor(Avalonia.Platform.IPlatformHandle)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public Avalonia.AvaloniaProperty Avalonia.AvaloniaProperty Avalonia.Controls.Notifications.NotificationCard.CloseOnClickProperty' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Controls.Platform.ITopLevelNativeMenuExporter.SetNativeMenu(Avalonia.Controls.NativeMenu)' is present in the contract but not in the implementation.
 EnumValuesMustMatch : Enum value 'Avalonia.Platform.ExtendClientAreaChromeHints Avalonia.Platform.ExtendClientAreaChromeHints.Default' is (System.Int32)2 in the implementation but (System.Int32)1 in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public System.Nullable<Avalonia.Size> Avalonia.Platform.ITopLevelImpl.FrameSize' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public System.Nullable<Avalonia.Size> Avalonia.Platform.ITopLevelImpl.FrameSize.get()' is present in the implementation but not in the contract.
@@ -56,4 +57,4 @@ InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platfor
 MembersMustExist : Member 'public void Avalonia.Platform.IWindowImpl.Resize(Avalonia.Size)' does not exist in the implementation but it does exist in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.IWindowImpl.Resize(Avalonia.Size, Avalonia.Platform.PlatformResizeReason)' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public Avalonia.Platform.ITrayIconImpl Avalonia.Platform.IWindowingPlatform.CreateTrayIcon()' is present in the implementation but not in the contract.
-Total Issues: 57
+Total Issues: 58

src/Avalonia.Controls/NativeMenu.Export.cs

@@ -52,15 +52,10 @@ namespace Avalonia.Controls
         }
 
         public static readonly AttachedProperty<NativeMenu> MenuProperty
-            = AvaloniaProperty.RegisterAttached<NativeMenu, AvaloniaObject, NativeMenu>("Menu"/*, validate:
-                (o, v) =>
-                {
-                    if(!(o is Application || o is TopLevel))
-                        throw new InvalidOperationException("NativeMenu.Menu property isn't valid on "+o.GetType());
-                    return v;
-                }*/);
+            = AvaloniaProperty.RegisterAttached<NativeMenu, AvaloniaObject, NativeMenu>("Menu");
 
         public static void SetMenu(AvaloniaObject o, NativeMenu menu) => o.SetValue(MenuProperty, menu);
+
         public static NativeMenu GetMenu(AvaloniaObject o) => o.GetValue(MenuProperty);
         
         static NativeMenu()
@@ -79,6 +74,10 @@ namespace Avalonia.Controls
                 {
                     GetInfo(tl).Exporter?.SetNativeMenu(args.NewValue.GetValueOrDefault());
                 }
+                else if(args.Sender is INativeMenuExporterProvider provider)
+                {
+                    provider.NativeMenuExporter?.SetNativeMenu(args.NewValue.GetValueOrDefault());
+                }
             });
         }
     }

src/Avalonia.Controls/Platform/ITopLevelNativeMenuExporter.cs

@@ -1,14 +1,25 @@
 using System;
-using System.Collections.Generic;
 using Avalonia.Platform;
 
+#nullable enable
+
 namespace Avalonia.Controls.Platform
 {
-    public interface ITopLevelNativeMenuExporter
+    public interface INativeMenuExporter
+    {
+        void SetNativeMenu(NativeMenu menu);
+    }
+
+    public interface ITopLevelNativeMenuExporter : INativeMenuExporter
     {
         bool IsNativeMenuExported { get; }
+
         event EventHandler OnIsNativeMenuExportedChanged;
-        void SetNativeMenu(NativeMenu menu);
+    }
+
+    public interface INativeMenuExporterProvider
+    {
+        INativeMenuExporter? NativeMenuExporter { get; }
     }
     
     public interface ITopLevelImplWithNativeMenuExporter : ITopLevelImpl

src/Avalonia.Controls/Platform/ITrayIconImpl.cs

@@ -1,5 +1,6 @@
 using System;
 using Avalonia.Controls;
+using Avalonia.Controls.Platform;
 
 #nullable enable
 
@@ -21,5 +22,7 @@ namespace Avalonia.Platform
         /// Sets if the tray icon is visible or not.
         /// </summary>
         void SetIsVisible (bool visible);
+
+        INativeMenuExporter? MenuExporter { get; }
     }
 }

src/Avalonia.Controls/TrayIcon.cs

@@ -12,7 +12,7 @@ namespace Avalonia.Controls
     {
     }
 
-    public class TrayIcon : AvaloniaObject, IDataContextProvider
+    public class TrayIcon : AvaloniaObject, IDataContextProvider, INativeMenuExporterProvider
     {
         private readonly ITrayIconImpl _impl;
 
@@ -141,6 +141,8 @@ namespace Avalonia.Controls
             set => SetValue(IsVisibleProperty, value);
         }
 
+        public INativeMenuExporter? NativeMenuExporter => _impl.MenuExporter;
+
         protected override void OnPropertyChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
         {
             base.OnPropertyChanged(change);

src/Avalonia.DesignerSupport/Remote/TrayIconStub.cs

@@ -1,4 +1,6 @@
 using System;
+using Avalonia.Controls;
+using Avalonia.Controls.Platform;
 using Avalonia.Platform;
 
 namespace Avalonia.DesignerSupport.Remote
@@ -9,6 +11,8 @@ namespace Avalonia.DesignerSupport.Remote
         public Action DoubleClicked { get; set; }
         public Action RightClicked { get; set; }
 
+        public INativeMenuExporter MenuExporter => throw new NotImplementedException();
+
         public void SetIcon(IWindowIconImpl icon)
         {   
         }
@@ -17,6 +21,11 @@ namespace Avalonia.DesignerSupport.Remote
         {   
         }
 
+        public void SetMenu(NativeMenu menu)
+        {
+            throw new NotImplementedException();
+        }
+
         public void SetToolTipText(string text)
         {
         }

src/Windows/Avalonia.Win32/TrayIconImpl.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using Avalonia.Controls;
+using Avalonia.Controls.Platform;
 using Avalonia.Controls.Primitives.PopupPositioning;
 using Avalonia.LogicalTree;
 using Avalonia.Platform;
@@ -21,9 +22,12 @@ namespace Avalonia.Win32
         private bool _iconAdded;
         private IconImpl? _icon;
         private string? _tooltipText;
+        private readonly Win32NativeToManagedMenuExporter _exporter;
 
         private static Dictionary<int, TrayIconImpl> s_trayIcons = new Dictionary<int, TrayIconImpl>();
 
+        public INativeMenuExporter MenuExporter => _exporter;
+
         internal static void ProcWnd(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam)
         {
             if (msg == (int)CustomWindowsMessage.WM_TRAYMOUSE && s_trayIcons.ContainsKey(wParam.ToInt32()))
@@ -34,6 +38,8 @@ namespace Avalonia.Win32
 
         public TrayIconImpl()
         {
+            _exporter = new Win32NativeToManagedMenuExporter();
+
             _uniqueId = ++_nextUniqueId;
 
             s_trayIcons.Add(_uniqueId, this);
@@ -125,7 +131,7 @@ namespace Avalonia.Win32
             }
         }
 
-        private static void OnRightClicked()
+        private void OnRightClicked()
         {
             var _trayMenu = new TrayPopupRoot()
             {
@@ -135,14 +141,7 @@ namespace Avalonia.Win32
                 TransparencyLevelHint = WindowTransparencyLevel.Transparent,
                 Content = new TrayIconMenuFlyoutPresenter()
                 {
-                    Items = new List<MenuItem>
-                                {
-                                    new MenuItem {  Header = "Item 1"},
-                                    new MenuItem {  Header = "Item 2"},
-                                    new MenuItem {  Header = "Item 3"},
-                                    new MenuItem {  Header = "Item 4"},
-                                    new MenuItem {  Header = "Item 5"}
-                                }
+                    Items = _exporter.GetMenu()
                 }
             };
 

src/Windows/Avalonia.Win32/Win32NativeToManagedMenuExporter.cs

@@ -0,0 +1,58 @@
+using System.Collections.Generic;
+using Avalonia.Controls;
+using Avalonia.Controls.Platform;
+
+#nullable enable
+
+namespace Avalonia.Win32
+{
+    internal class Win32NativeToManagedMenuExporter : INativeMenuExporter
+    {
+        private NativeMenu? _nativeMenu;
+
+        public void SetNativeMenu(NativeMenu nativeMenu)
+        {
+            _nativeMenu = nativeMenu;
+        }
+
+        private IEnumerable<MenuItem>? Populate (NativeMenu nativeMenu)
+        {
+            var items = new List<MenuItem>();
+
+            foreach (var menuItem in nativeMenu.Items)
+            {
+                if (menuItem is NativeMenuItemSeparator separator)
+                {
+                    items.Add(new MenuItem { Header = "-" });   
+                }
+                else if (menuItem is NativeMenuItem item)
+                {
+                    var newItem = new MenuItem { Header = item.Header, Icon = item.Icon, Command = item.Command, CommandParameter = item.CommandParameter };
+
+                    if(item.Menu != null)
+                    {
+                        newItem.ContextMenu = new ContextMenu() { Items = Populate(item.Menu) };
+                    }
+                    else if (item.HasClickHandlers && item is INativeMenuItemExporterEventsImplBridge bridge)
+                    {
+                        newItem.Click += (_,_) => bridge.RaiseClicked();
+                    }
+
+                    items.Add(newItem);
+                }
+            }
+
+            return items;
+        }
+
+        public IEnumerable<MenuItem>? GetMenu ()
+        {
+            if(_nativeMenu != null)
+            {
+                return Populate(_nativeMenu);
+            }
+
+            return null;
+        }
+    }
+}