feat: implement separator.

demo/Ursa.Demo/Converters/MenuDataTemplateSelector.cs

@@ -0,0 +1,27 @@
+using Avalonia.Controls;
+using Avalonia.Controls.Templates;
+using Ursa.Demo.ViewModels;
+
+namespace Ursa.Demo.Converters;
+
+public class MenuDataTemplateSelector: IDataTemplate
+{
+    public IDataTemplate? MenuTemplate { get; set; }
+    public IDataTemplate? SeparatorTemplate { get; set; }
+    
+    public Control? Build(object? param)
+    {
+        if (param is NavigationMenuItemViewModel vm)
+        {
+            if (vm.IsSeparator) return SeparatorTemplate?.Build(vm);
+            else return MenuTemplate?.Build(vm);
+        }
+
+        return null;
+    }
+
+    public bool Match(object? data)
+    {
+        return true;
+    }
+}

demo/Ursa.Demo/Pages/NavigationMenuDemo.axaml

@@ -21,6 +21,8 @@
         </converters:IconNameConverter>
     </UserControl.Resources>
     <StackPanel Orientation="Horizontal">
+        <ThemeVariantScope RequestedThemeVariant="Light">
+            <Border Padding="4" Theme="{DynamicResource CardBorder}">
                 <u:NavigationMenu
                     Name="menu"
                     HorizontalAlignment="Left"
@@ -39,7 +41,9 @@
                             Data="M10.6201 17.5C6.06377 17.5 2.37012 13.8063 2.37012 9.25C2.37012 4.69365 6.06377 1 10.6201 1V17.5ZM13.3701 6.5C17.9265 6.5 21.6201 10.1936 21.6201 14.75C21.6201 19.3063 17.9265 23 13.3701 23V6.5Z" />
                     </u:NavigationMenu.Icon>
                     <u:NavigationMenu.ItemTemplate>
-                <TreeDataTemplate>
+                        <converters:MenuDataTemplateSelector>
+                            <converters:MenuDataTemplateSelector.MenuTemplate>
+                                <DataTemplate DataType="vm:NavigationMenuItemViewModel">
                                     <u:NavigationMenuItem Header="{Binding MenuHeader}" ItemsSource="{Binding Children}">
                                         <u:NavigationMenuItem.Icon>
                                             <PathIcon
@@ -48,8 +52,17 @@
                                                 Data="{Binding MenuIconName, Converter={StaticResource IconNameConverter}}" />
                                         </u:NavigationMenuItem.Icon>
                                     </u:NavigationMenuItem>
-                </TreeDataTemplate>
+                                </DataTemplate>
+                            </converters:MenuDataTemplateSelector.MenuTemplate>
+                            <converters:MenuDataTemplateSelector.SeparatorTemplate>
+                                <DataTemplate DataType="vm:NavigationMenuItemViewModel">
+                                    <u:NavigationMenuSeparator Header="{Binding MenuHeader}" />
+                                </DataTemplate>
+                            </converters:MenuDataTemplateSelector.SeparatorTemplate>
+                        </converters:MenuDataTemplateSelector>
                     </u:NavigationMenu.ItemTemplate>
                 </u:NavigationMenu>
+            </Border>
+        </ThemeVariantScope>
     </StackPanel>
 </UserControl>

demo/Ursa.Demo/ViewModels/NavigationMenuDemoViewModel.cs

@@ -25,6 +25,11 @@ public class NavigationMenuDemoViewModel: ObservableObject
             }
         },
         new NavigationMenuItemViewModel()
+        {
+            MenuHeader = "附加功能",
+            IsSeparator = true,
+        },
+        new NavigationMenuItemViewModel()
         {
             MenuHeader = "任务平台",
             MenuIconName = "Gear",
@@ -41,5 +46,7 @@ public class NavigationMenuItemViewModel: ObservableObject
 {
     public string MenuHeader { get; set; }
     public string MenuIconName { get; set; }
+    
+    public bool IsSeparator { get; set; }
     public ObservableCollection<NavigationMenuItemViewModel> Children { get; set; } = new();
 }

src/Ursa.Themes.Semi/Controls/Navigation.axaml

@@ -297,4 +297,40 @@
             <Setter Property="PathIcon.IsVisible" Value="False" />
         </Style>
     </ControlTheme>
+
+    <ControlTheme x:Key="{x:Type u:NavigationMenuSeparator}" TargetType="u:NavigationMenuSeparator">
+        <Setter Property="Template">
+            <ControlTemplate TargetType="u:NavigationMenuSeparator">
+                <StackPanel Name="PART_RootPanel" Margin="4,0">
+                    <ContentPresenter
+                        Name="PART_HeaderPresenter"
+                        Margin="4,0"
+                        HorizontalAlignment="Left"
+                        Content="{TemplateBinding Header}"
+                        ContentTemplate="{TemplateBinding HeaderTemplate}"
+                        Foreground="{DynamicResource TextBlockQuaternaryForeground}"
+                        IsVisible="{TemplateBinding Header,
+                                                    Converter={x:Static ObjectConverters.IsNotNull}}">
+                        <ContentPresenter.Styles>
+                            <Style Selector="TextBlock">
+                                <Setter Property="FontSize" Value="12" />
+                            </Style>
+                        </ContentPresenter.Styles>
+                    </ContentPresenter>
+                    <Rectangle
+                        Height="1"
+                        Margin="0,2"
+                        HorizontalAlignment="Stretch"
+                        Fill="{DynamicResource SemiColorBorder}" />
+                </StackPanel>
+            </ControlTemplate>
+        </Setter>
+        <Style Selector="^:closed /template/ StackPanel#PART_RootPanel">
+            <Setter Property="StackPanel.HorizontalAlignment" Value="Center" />
+            <Setter Property="StackPanel.Width" Value="32" />
+        </Style>
+        <Style Selector="^:closed /template/ ContentPresenter#PART_HeaderPresenter">
+            <Setter Property="ContentPresenter.IsVisible" Value="False" />
+        </Style>
+    </ControlTheme>
 </ResourceDictionary>

src/Ursa/Controls/Navigation/NavigationMenuSeparator.cs

@@ -1,6 +1,11 @@
+using Avalonia.Input;
+
 namespace Ursa.Controls;
 
 public class NavigationMenuSeparator: NavigationMenuItem
 {
-    
+    protected override void OnPointerPressed(PointerPressedEventArgs e)
+    {
+        e.Handled = true;
+    }
 }