WIP: inherit binding from root.

demo/Ursa.Demo/Pages/NavMenuDemo.axaml

@@ -1,27 +1,54 @@
-<UserControl xmlns="https://github.com/avaloniaui"
+<UserControl
-             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    x:Class="Ursa.Demo.Pages.NavMenuDemo"
-             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns="https://github.com/avaloniaui"
-             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:u="https://irihi.tech/ursa"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
-             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
-             x:Class="Ursa.Demo.Pages.NavMenuDemo">
+    xmlns:u="https://irihi.tech/ursa"
-    <u:NavMenu Name="menu">
+    xmlns:vm="using:Ursa.Demo.ViewModels"
-        <u:NavMenuItem Header="Menu 1">
+    d:DesignHeight="450"
-            <u:NavMenuItem.Icon>
+    d:DesignWidth="800"
-                <Rectangle Width="10" Height="10" Fill="Red"></Rectangle>
+    x:CompileBindings="True"
-            </u:NavMenuItem.Icon>
+    x:DataType="vm:NavMenuDemoViewModel"
-        </u:NavMenuItem>
+    mc:Ignorable="d">
-        <u:NavMenuItem Header="Menu 2">
+    <StackPanel>
-            <u:NavMenuItem.Icon>
+        <u:NavMenu>
-                <Rectangle Width="20" Height="10" Fill="Red"></Rectangle>
+            <u:NavMenuItem Header="Menu 1">
-            </u:NavMenuItem.Icon>
+                <u:NavMenuItem.Icon>
-        </u:NavMenuItem>
+                    <Rectangle
-        <u:NavMenuItem Header="Menu 3">
+                        Width="10"
-            <u:NavMenuItem.Icon>
+                        Height="10"
-                <Rectangle Width="30" Height="10" Fill="Red"></Rectangle>
+                        Fill="Red" />
-            </u:NavMenuItem.Icon>
+                </u:NavMenuItem.Icon>
-        </u:NavMenuItem>
+                <u:NavMenuItem Header="Sub Menu 1"></u:NavMenuItem>
-        <u:Divider Content="Divider"></u:Divider>
+                <u:NavMenuItem Header="Sub Menu 2"></u:NavMenuItem>
-        <TextBlock Text="{Binding #menu.SelectedItem}"></TextBlock>
+                <u:NavMenuItem Header="Sub Menu 3"></u:NavMenuItem>
-    </u:NavMenu>
+            </u:NavMenuItem>
+            <u:NavMenuItem Header="Menu 2">
+                <u:NavMenuItem.Icon>
+                    <Rectangle
+                        Width="20"
+                        Height="10"
+                        Fill="Red" />
+                </u:NavMenuItem.Icon>
+            </u:NavMenuItem>
+            <u:NavMenuItem Header="Menu 3">
+                <u:NavMenuItem.Icon>
+                    <Rectangle
+                        Width="30"
+                        Height="10"
+                        Fill="Red" />
+                </u:NavMenuItem.Icon>
+            </u:NavMenuItem>
+        </u:NavMenu>
+        <u:Divider Content="Divider" />
+        <TextBlock Text="{ReflectionBinding #menu.SelectedItem.Header}" />
+        <u:NavMenu
+            Name="menu"
+            ItemsSource="{Binding MenuItems}"
+            HeaderBinding="{Binding Header}"
+            SubMenuBinding="{Binding  Children}"
+            IconBinding="{Binding Header}"/>
+    </StackPanel>
+    
 </UserControl>

demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs

@@ -1,6 +1,7 @@
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Markup.Xaml;
+using Ursa.Demo.ViewModels;
 
 namespace Ursa.Demo.Pages;
 
@@ -9,5 +10,6 @@ public partial class NavMenuDemo : UserControl
     public NavMenuDemo()
     {
         InitializeComponent();
+        this.DataContext = new NavMenuDemoViewModel();
     }
 }

demo/Ursa.Demo/ViewModels/NavMenuDemoViewModel.cs

@@ -1,8 +1,49 @@
-using CommunityToolkit.Mvvm.ComponentModel;
+using System.Collections.ObjectModel;
+using CommunityToolkit.Mvvm.ComponentModel;
 
 namespace Ursa.Demo.ViewModels;
 
 public class NavMenuDemoViewModel: ObservableObject
 {
-    
+    public ObservableCollection<MenuItem> MenuItems { get; set; } = new ObservableCollection<MenuItem>
+    {
+        new MenuItem { Header = "Introduction" , Children =
+        {
+            new MenuItem() { Header = "Getting Started" },
+            new MenuItem() { Header = "Design Principles" },
+            new MenuItem() { Header = "Contributing" },
+        }},
+        new MenuItem { Header = "Badge" },
+        new MenuItem { Header = "Banner" },
+        new MenuItem { Header = "ButtonGroup" },
+        new MenuItem { Header = "Class Input" },
+        new MenuItem { Header = "Dialog" },
+        new MenuItem { Header = "Divider" },
+        new MenuItem { Header = "Drawer" },
+        new MenuItem { Header = "DualBadge" },
+        new MenuItem { Header = "EnumSelector" },
+        new MenuItem { Header = "ImageViewer" },
+        new MenuItem { Header = "IPv4Box" },
+        new MenuItem { Header = "IconButton" },
+        new MenuItem { Header = "KeyGestureInput" },
+        new MenuItem { Header = "Loading" },
+        new MenuItem { Header = "MessageBox" },
+        new MenuItem { Header = "Navigation" },
+        new MenuItem { Header = "NavMenu" },
+        new MenuItem { Header = "NumericUpDown" },
+        new MenuItem { Header = "Pagination" },
+        new MenuItem { Header = "RangeSlider" },
+        new MenuItem { Header = "SelectionList" },
+        new MenuItem { Header = "TagInput" },
+        new MenuItem { Header = "Timeline" },
+        new MenuItem { Header = "TwoTonePathIcon" },
+        new MenuItem { Header = "ThemeToggler" }
+    };
+}
+
+public class MenuItem
+{
+    public string? Header { get; set; }
+    public string? Icon { get; set; }
+    public ObservableCollection<MenuItem> Children { get; set; } = new ObservableCollection<MenuItem>();
 }

src/Ursa/Controls/NavMenu/NavMenu.cs

@@ -4,6 +4,7 @@ using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
 using Avalonia.Data;
 using Avalonia.LogicalTree;
+using Avalonia.Metadata;
 
 namespace Ursa.Controls;
 
@@ -18,6 +19,39 @@ public class NavMenu: ItemsControl
         set => SetValue(SelectedItemProperty, value);
     }
 
+    public static readonly StyledProperty<IBinding?> IconBindingProperty = AvaloniaProperty.Register<NavMenu, IBinding?>(
+        nameof(IconBinding));
+
+    [AssignBinding]
+    [InheritDataTypeFromItems(nameof(ItemsSource))]
+    public IBinding? IconBinding
+    {
+        get => GetValue(IconBindingProperty);
+        set => SetValue(IconBindingProperty, value);
+    }
+
+    public static readonly StyledProperty<IBinding?> HeaderBindingProperty = AvaloniaProperty.Register<NavMenu, IBinding?>(
+        nameof(HeaderBinding));
+
+    [AssignBinding]
+    [InheritDataTypeFromItems(nameof(ItemsSource))]
+    public IBinding? HeaderBinding
+    {
+        get => GetValue(HeaderBindingProperty);
+        set => SetValue(HeaderBindingProperty, value);
+    }
+
+    public static readonly StyledProperty<IBinding?> SubMenuBindingProperty = AvaloniaProperty.Register<NavMenu, IBinding?>(
+        nameof(SubMenuBinding));
+
+    [AssignBinding]
+    [InheritDataTypeFromItems(nameof(ItemsSource))]
+    public IBinding? SubMenuBinding
+    {
+        get => GetValue(SubMenuBindingProperty);
+        set => SetValue(SubMenuBindingProperty, value);
+    }
+
     static NavMenu()
     {
         SelectedItemProperty.Changed.AddClassHandler<NavMenu, object?>((o, e) => o.OnSelectedItemChange(e));
@@ -37,7 +71,27 @@ public class NavMenu: ItemsControl
     {
         return new NavMenuItem();
     }
-    
+
+    protected override void PrepareContainerForItemOverride(Control container, object? item, int index)
+    {
+        base.PrepareContainerForItemOverride(container, item, index);
+        if (container is NavMenuItem navMenuItem)
+        {
+            if (IconBinding is not null)
+            {
+                navMenuItem[!NavMenuItem.IconProperty] = IconBinding;
+            }
+            if (HeaderBinding is not null)
+            {
+                navMenuItem[!HeaderedItemsControl.HeaderProperty] = HeaderBinding;
+            }
+            if (SubMenuBinding is not null)
+            {
+                navMenuItem[!ItemsSourceProperty] = SubMenuBinding;
+            }
+        }
+    }
+
     internal void SelectItem(NavMenuItem item)
     {
         if (item.IsSelected) return;

src/Ursa/Controls/NavMenu/NavMenuItem.cs

@@ -1,5 +1,7 @@
-using Avalonia;
+using System.Windows.Input;
+using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Controls.Metadata;
 using Avalonia.Controls.Mixins;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
@@ -9,8 +11,11 @@ using Avalonia.VisualTree;
 
 namespace Ursa.Controls;
 
+[PseudoClasses(PC_Highlighted)]
 public class NavMenuItem: HeaderedSelectingItemsControl
 {
+    public const string PC_Highlighted = "highlighted";
+    
     private NavMenu? _rootMenu;
     
     public static readonly StyledProperty<object?> IconProperty = AvaloniaProperty.Register<NavMenuItem, object?>(
@@ -31,6 +36,15 @@ public class NavMenuItem: HeaderedSelectingItemsControl
         set => SetValue(IconTemplateProperty, value);
     }
 
+    public static readonly StyledProperty<ICommand?> CommandProperty = AvaloniaProperty.Register<NavMenuItem, ICommand?>(
+        nameof(Command));
+
+    public ICommand? Command
+    {
+        get => GetValue(CommandProperty);
+        set => SetValue(CommandProperty, value);
+    }
+
     public new static readonly StyledProperty<bool> IsSelectedProperty =
         SelectingItemsControl.IsSelectedProperty.AddOwner<NavMenuItem>();
 
@@ -39,6 +53,8 @@ public class NavMenuItem: HeaderedSelectingItemsControl
         get => GetValue(IsSelectedProperty);
         set => SetValue(IsSelectedProperty, value);
     }
+    
+    
 
     static NavMenuItem()
     {
@@ -56,26 +72,34 @@ public class NavMenuItem: HeaderedSelectingItemsControl
         return new NavMenuItem();
     }
 
+    protected override void PrepareContainerForItemOverride(Control container, object? item, int index)
+    {
+        base.PrepareContainerForItemOverride(container, item, index);
+        if (container is NavMenuItem navMenuItem)
+        {
+            if (_rootMenu?.HeaderBinding is not null)
+            {
+                container[!HeaderProperty] = _rootMenu.HeaderBinding;
+            }
+        }
+    }
+
     protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
     {
         base.OnAttachedToVisualTree(e);
         _rootMenu = GetRootMenu();
-        UpdateSelection(1);
     }
 
     protected override void OnPointerPressed(PointerPressedEventArgs e)
     {
         base.OnPointerPressed(e);
         _rootMenu?.SelectItem(this);
+        e.Handled = true;
     }
 
     private NavMenu? GetRootMenu()
     {
-        var root = this.FindAncestorOfType<NavMenu>();
+        var root = this.FindAncestorOfType<NavMenu>() ?? this.FindLogicalAncestorOfType<NavMenu>();
-        if (root is null)
-        {
-            root = this.FindLogicalAncestorOfType<NavMenu>();
-        }
         return root;
     }
 }