Merge pull request #7422 from robloo/robloo-SplitButton

Add SplitButton & ToggleSplitButton

samples/ControlCatalog/MainView.xaml

@@ -22,8 +22,8 @@
       <TabItem Header="Border">
         <pages:BorderPage />
       </TabItem>
-      <TabItem Header="Button">
-        <pages:ButtonPage />
+      <TabItem Header="Buttons">
+        <pages:ButtonsPage />
       </TabItem>
       <TabItem Header="ButtonSpinner">
         <pages:ButtonSpinnerPage />

samples/ControlCatalog/Pages/ButtonPage.xaml

@@ -1,45 +0,0 @@
-<UserControl xmlns="https://github.com/avaloniaui"
-             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             x:Class="ControlCatalog.Pages.ButtonPage">
-  <StackPanel Orientation="Vertical" Spacing="4">
-    <TextBlock Classes="h2">A button control</TextBlock>
-
-    <StackPanel Orientation="Horizontal"
-                Margin="0,16,0,0"
-                HorizontalAlignment="Center"
-                Spacing="16">
-      <StackPanel Orientation="Vertical" Spacing="8" Width="200">
-        <Button>Standard _XAML Button</Button>
-        <Button Foreground="White">Foreground</Button>
-        <Button Background="{DynamicResource SystemAccentColor}">Background</Button>
-        <Button IsEnabled="False">Disabled</Button>
-        <Button Content="Re-themed">
-          <Button.Styles>
-            <Style>
-              <Style.Resources>
-                <SolidColorBrush x:Key="ThemeBorderMidBrush">Red</SolidColorBrush>
-                <SolidColorBrush x:Key="ThemeControlHighBrush">DarkRed</SolidColorBrush>
-                <SolidColorBrush x:Key="ButtonBorderBrush">Red</SolidColorBrush>
-                <SolidColorBrush x:Key="ButtonBackground">DarkRed</SolidColorBrush>
-                <SolidColorBrush x:Key="ButtonBackgroundPointerOver">Red</SolidColorBrush>
-                <SolidColorBrush x:Key="ButtonBackgroundPressed">OrangeRed</SolidColorBrush>
-              </Style.Resources>
-            </Style>
-          </Button.Styles>          
-        </Button>
-        <RepeatButton Name="RepeatButton">
-          <TextBlock Name="RepeatButtonTextBlock" Text="Repeat Button: 0" />
-        </RepeatButton>
-        <ToggleButton Content="Toggle Button"/>
-    </StackPanel>
-
-      <StackPanel Orientation="Vertical" Spacing="8" Width="150">
-        <Button BorderThickness="0">No Border</Button>
-        <Button BorderBrush="{DynamicResource SystemAccentColor}">Border Color</Button>
-        <Button BorderBrush="{DynamicResource SystemAccentColor}" BorderThickness="4">Thick Border</Button>
-        <Button BorderBrush="{DynamicResource SystemAccentColor}" BorderThickness="4" IsEnabled="False">Disabled</Button>
-        <Button BorderBrush="{DynamicResource SystemAccentColor}" KeyboardNavigation.IsTabStop="False">IsTabStop=False</Button>
-      </StackPanel>
-    </StackPanel>    
-  </StackPanel>
-</UserControl>

samples/ControlCatalog/Pages/ButtonsPage.xaml

@@ -0,0 +1,224 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             x:Class="ControlCatalog.Pages.ButtonsPage">
+
+  <UserControl.Resources>
+
+    <MenuFlyout x:Key="SharedMenuFlyout"
+                Placement="Bottom">
+      <MenuItem Header="Item 1">
+        <MenuItem Header="Subitem 1" />
+        <MenuItem Header="Subitem 2" />
+        <MenuItem Header="Subitem 3" />
+      </MenuItem>
+      <MenuItem Header="Item 2"
+                InputGesture="Ctrl+A" />
+      <MenuItem Header="Item 3" />
+    </MenuFlyout>
+
+  </UserControl.Resources>
+      
+  <UserControl.Styles >
+
+    <Style Selector="Border.header-border">
+      <Setter Property="Background">
+        <Setter.Value>
+          <SolidColorBrush Color="Gray" Opacity="0.5" />
+        </Setter.Value>
+      </Setter>
+      <Setter Property="BorderBrush" Value="Gray" />
+      <Setter Property="BorderThickness" Value="0.5" />
+      <Setter Property="CornerRadius" Value="5,5,0,0" />
+      <Setter Property="MaxWidth" Value="450" />
+      <Setter Property="Padding" Value="10" />
+    </Style>
+    
+    <Style Selector="TextBlock.header">
+      <Setter Property="FontSize" Value="18" />
+      <Setter Property="FontWeight" Value="Bold" />
+    </Style>
+
+    <Style Selector="Border.thin">
+      <Setter Property="BorderBrush" Value="Gray" />
+      <Setter Property="BorderThickness" Value="0.5" />
+      <Setter Property="CornerRadius" Value="0,0,5,5" />
+      <Setter Property="Margin" Value="0,0,0,15" />
+    </Style>
+
+  </UserControl.Styles>
+
+  <!-- Styles and overall page design based on AcrylicPage -->
+
+  <StackPanel Orientation="Vertical"
+              Width="450">
+
+    <!-- Button -->
+    <Border Classes="header-border">
+      <StackPanel Orientation="Vertical"
+                  Spacing="4">
+        <TextBlock Text="Button" Classes="header" />
+        <TextBlock TextWrapping="Wrap">A standard button control</TextBlock>
+      </StackPanel>
+    </Border>
+
+    <Border Classes="thin"
+            Padding="15">
+      <StackPanel Orientation="Horizontal"
+                  HorizontalAlignment="Center"
+                  Spacing="10">
+        <StackPanel Orientation="Vertical"
+                    Spacing="8"
+                    Width="200">
+          <Button>Standard _XAML Button</Button>
+          <Button Foreground="White">Foreground</Button>
+          <Button Background="{DynamicResource SystemAccentColor}">Background</Button>
+          <Button IsEnabled="False">Disabled</Button>
+          <Button Content="Re-themed">
+            <Button.Styles>
+              <Style>
+                <Style.Resources>
+                  <SolidColorBrush x:Key="ThemeBorderMidBrush">Red</SolidColorBrush>
+                  <SolidColorBrush x:Key="ThemeControlHighBrush">DarkRed</SolidColorBrush>
+                  <SolidColorBrush x:Key="ButtonBorderBrush">Red</SolidColorBrush>
+                  <SolidColorBrush x:Key="ButtonBackground">DarkRed</SolidColorBrush>
+                  <SolidColorBrush x:Key="ButtonBackgroundPointerOver">Red</SolidColorBrush>
+                  <SolidColorBrush x:Key="ButtonBackgroundPressed">OrangeRed</SolidColorBrush>
+                  <SolidColorBrush x:Key="ButtonForeground">White</SolidColorBrush>
+                  <SolidColorBrush x:Key="ButtonForegroundPointerOver">Black</SolidColorBrush>
+                  <SolidColorBrush x:Key="ButtonForegroundPressed">Black</SolidColorBrush>
+                </Style.Resources>
+              </Style>
+            </Button.Styles>
+          </Button>
+        </StackPanel>
+
+        <StackPanel Orientation="Vertical"
+                    Spacing="8"
+                    Width="200">
+          <Button BorderThickness="0">No Border</Button>
+          <Button BorderBrush="{DynamicResource SystemAccentColor}">Border Color</Button>
+          <Button BorderBrush="{DynamicResource SystemAccentColor}"
+                  BorderThickness="4">Thick Border</Button>
+          <Button BorderBrush="{DynamicResource SystemAccentColor}"
+                  BorderThickness="4"
+                  IsEnabled="False">Disabled</Button>
+          <Button BorderBrush="{DynamicResource SystemAccentColor}"
+                  KeyboardNavigation.IsTabStop="False">IsTabStop=False</Button>
+        </StackPanel>
+      </StackPanel>
+    </Border>
+
+    <!-- ToggleButton -->
+    <Border Classes="header-border">
+      <StackPanel Orientation="Vertical"
+                  Spacing="4">
+        <TextBlock Text="ToggleButton"
+                   Classes="header" />
+        <TextBlock TextWrapping="Wrap">A button control with multiple states: checked, unchecked or indeterminate.</TextBlock>
+      </StackPanel>
+    </Border>
+
+    <Border Classes="thin"
+            Padding="15">
+      <StackPanel Orientation="Vertical"
+                  Spacing="8">
+        <ToggleButton Content="Toggle Button" />
+      </StackPanel>
+    </Border>
+
+    <!-- RepeatButton -->
+    <Border Classes="header-border">
+      <StackPanel Orientation="Vertical"
+                  Spacing="4">
+        <TextBlock Text="RepeatButton"
+                   Classes="header" />
+        <TextBlock TextWrapping="Wrap">A button control that raises its Click event repeatedly when it is pressed and held.</TextBlock>
+      </StackPanel>
+    </Border>
+
+    <Border Classes="thin"
+            Padding="15">
+      <StackPanel Orientation="Vertical"
+                  Spacing="8">
+        <RepeatButton Name="RepeatButton">
+          <TextBlock Name="RepeatButtonTextBlock"
+                     Text="Repeat Button: 0" />
+        </RepeatButton>
+      </StackPanel>
+    </Border>
+
+    <!-- SplitButton -->
+    <Border Classes="header-border">
+      <StackPanel Orientation="Vertical"
+                  Spacing="4">
+        <TextBlock Text="SplitButton"
+                   Classes="header" />
+        <TextBlock TextWrapping="Wrap">A button with primary and secondary parts that can each be pressed separately. The primary part behaves like a Button and the secondary part opens a flyout.</TextBlock>
+      </StackPanel>
+    </Border>
+
+    <Border Classes="thin"
+            Padding="15">
+      <StackPanel Orientation="Vertical"
+                  Spacing="8">
+        <SplitButton Flyout="{StaticResource SharedMenuFlyout}">
+          <TextBlock Text="Content" />
+        </SplitButton>
+        <SplitButton IsEnabled="False"
+                     Flyout="{StaticResource SharedMenuFlyout}">
+          <TextBlock Text="Disabled" />
+        </SplitButton>
+        <SplitButton Flyout="{StaticResource SharedMenuFlyout}"
+                     Content="Re-themed">
+          <SplitButton.Styles>
+            <Style>
+              <Style.Resources>
+                <x:Double x:Key="SplitButtonSeparatorWidth">1.5</x:Double>
+                <Thickness x:Key="SplitButtonBorderThemeThickness">2</Thickness>
+                <SolidColorBrush x:Key="SplitButtonBorderBrush">Red</SolidColorBrush>
+                <SolidColorBrush x:Key="SplitButtonBorderBrushPointerOver">Red</SolidColorBrush>
+                <SolidColorBrush x:Key="SplitButtonBorderBrushPressed">Red</SolidColorBrush>
+                <SolidColorBrush x:Key="SplitButtonBackground">DarkRed</SolidColorBrush>
+                <SolidColorBrush x:Key="SplitButtonBackgroundPointerOver">Red</SolidColorBrush>
+                <SolidColorBrush x:Key="SplitButtonBackgroundPressed">OrangeRed</SolidColorBrush>
+                <SolidColorBrush x:Key="SplitButtonForeground">White</SolidColorBrush>
+                <SolidColorBrush x:Key="SplitButtonForegroundPointerOver">Black</SolidColorBrush>
+                <SolidColorBrush x:Key="SplitButtonForegroundPressed">Black</SolidColorBrush>
+              </Style.Resources>
+            </Style>
+          </SplitButton.Styles>
+        </SplitButton>
+      </StackPanel>
+    </Border>
+
+    <!-- ToggleSplitButton -->
+    <Border Classes="header-border">
+      <StackPanel Orientation="Vertical"
+                  Spacing="4">
+        <TextBlock Text="ToggleSplitButton"
+                   Classes="header" />
+        <TextBlock TextWrapping="Wrap">A button with primary and secondary parts that can each be pressed separately. The primary part behaves like a ToggleButton with two states and the secondary part opens a flyout.</TextBlock>
+      </StackPanel>
+    </Border>
+
+    <Border Classes="thin"
+            Padding="15">
+      <StackPanel Orientation="Vertical"
+                  Spacing="8">
+        <ToggleSplitButton Flyout="{StaticResource SharedMenuFlyout}">
+          <TextBlock Text="Content" />
+        </ToggleSplitButton>
+        <ToggleSplitButton IsChecked="True"
+                           Flyout="{StaticResource SharedMenuFlyout}">
+          <TextBlock Text="Content" />
+        </ToggleSplitButton>
+        <ToggleSplitButton IsChecked="True"
+                           IsEnabled="False"
+                           Flyout="{StaticResource SharedMenuFlyout}">
+          <TextBlock Text="Disabled" />
+        </ToggleSplitButton>
+      </StackPanel>
+    </Border>
+
+  </StackPanel>
+</UserControl>

samples/ControlCatalog/Pages/ButtonPage.xaml.cs → samples/ControlCatalog/Pages/ButtonsPage.xaml.cs

@@ -3,11 +3,11 @@ using Avalonia.Markup.Xaml;
 
 namespace ControlCatalog.Pages
 {
-    public class ButtonPage : UserControl
+    public class ButtonsPage : UserControl
     {
         private int repeatButtonClickCount = 0;
 
-        public ButtonPage()
+        public ButtonsPage()
         {
             InitializeComponent();
 

samples/ControlCatalog/Pages/ToggleSwitchPage.xaml

@@ -11,7 +11,7 @@
       </StackPanel>
     </Border>
 
-    <TextBlock Text="headered ToggleSwitch" Classes="header"/>
+    <TextBlock Text="Headered ToggleSwitch" Classes="header"/>
 
     <Border Classes="Thin">
       <StackPanel>

src/Avalonia.Controls/Button.cs

@@ -85,8 +85,8 @@ namespace Avalonia.Controls
         /// <summary>
         /// Defines the <see cref="Flyout"/> property
         /// </summary>
-        public static readonly StyledProperty<FlyoutBase> FlyoutProperty =
-            AvaloniaProperty.Register<Button, FlyoutBase>(nameof(Flyout));
+        public static readonly StyledProperty<FlyoutBase?> FlyoutProperty =
+            AvaloniaProperty.Register<Button, FlyoutBase?>(nameof(Flyout));
 
         private ICommand? _command;
         private bool _commandCanExecute = true;
@@ -186,7 +186,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets or sets the Flyout that should be shown with this button.
         /// </summary>
-        public FlyoutBase Flyout
+        public FlyoutBase? Flyout
         {
             get => GetValue(FlyoutProperty);
             set => SetValue(FlyoutProperty, value);

src/Avalonia.Controls/SplitButton/SplitButton.cs

@@ -0,0 +1,485 @@
+using System;
+using System.Windows.Input;
+using Avalonia.Controls.Metadata;
+using Avalonia.Controls.Mixins;
+using Avalonia.Controls.Primitives;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.LogicalTree;
+
+namespace Avalonia.Controls
+{
+    /// <summary>
+    /// A button with primary and secondary parts that can each be pressed separately.
+    /// The primary part behaves like a <see cref="Button"/> and the secondary part opens a flyout.
+    /// </summary>
+    [PseudoClasses(pcFlyoutOpen, pcPressed)]
+    public class SplitButton : ContentControl, ICommandSource
+    {
+        protected const string pcChecked    = ":checked";
+        protected const string pcPressed    = ":pressed";
+        protected const string pcFlyoutOpen = ":flyout-open";
+
+        /// <summary>
+        /// Raised when the user presses the primary part of the <see cref="SplitButton"/>.
+        /// </summary>
+        public event EventHandler<RoutedEventArgs> Click
+        {
+            add => AddHandler(ClickEvent, value);
+            remove => RemoveHandler(ClickEvent, value);
+        }
+
+        /// <summary>
+        /// Defines the <see cref="Click"/> event.
+        /// </summary>
+        public static readonly RoutedEvent<RoutedEventArgs> ClickEvent =
+            RoutedEvent.Register<SplitButton, RoutedEventArgs>(nameof(Click), RoutingStrategies.Bubble);
+
+        /// <summary>
+        /// Defines the <see cref="Command"/> property.
+        /// </summary>
+        public static readonly DirectProperty<SplitButton, ICommand?> CommandProperty =
+            Button.CommandProperty.AddOwner<SplitButton>(
+                splitButton => splitButton.Command,
+                (splitButton, command) => splitButton.Command = command);
+
+        /// <summary>
+        /// Defines the <see cref="CommandParameter"/> property.
+        /// </summary>
+        public static readonly StyledProperty<object?> CommandParameterProperty =
+            Button.CommandParameterProperty.AddOwner<SplitButton>();
+
+        /// <summary>
+        /// Defines the <see cref="Flyout"/> property
+        /// </summary>
+        public static readonly StyledProperty<FlyoutBase?> FlyoutProperty =
+            Button.FlyoutProperty.AddOwner<SplitButton>();
+
+        private ICommand? _Command;
+
+        private Button? _primaryButton   = null;
+        private Button? _secondaryButton = null;
+
+        private bool _commandCanExecute       = true;
+        private bool _isAttachedToLogicalTree = false;
+        private bool _isFlyoutOpen            = false;
+        private bool _isKeyboardPressed       = false;
+
+        private IDisposable? _flyoutPropertyChangedDisposable;
+
+        ////////////////////////////////////////////////////////////////////////
+        // Constructor / Destructors
+        ////////////////////////////////////////////////////////////////////////
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SplitButton"/> class.
+        /// </summary>
+        public SplitButton()
+        {
+        }
+
+        ////////////////////////////////////////////////////////////////////////
+        // Properties
+        ////////////////////////////////////////////////////////////////////////
+
+        /// <summary>
+        /// Gets or sets the <see cref="ICommand"/> invoked when the primary part is pressed.
+        /// </summary>
+        public ICommand? Command
+        {
+            get => _Command;
+            set => SetAndRaise(CommandProperty, ref _Command, value);
+        }
+
+        /// <summary>
+        /// Gets or sets a parameter to be passed to the <see cref="Command"/>.
+        /// </summary>
+        public object? CommandParameter
+        {
+            get => GetValue(CommandParameterProperty);
+            set => SetValue(CommandParameterProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the <see cref="FlyoutBase"/> that is shown when the secondary part is pressed.
+        /// </summary>
+        public FlyoutBase? Flyout
+        {
+            get => GetValue(FlyoutProperty);
+            set => SetValue(FlyoutProperty, value);
+        }
+
+        /// <summary>
+        /// Gets a value indicating whether the button is currently checked.
+        /// </summary>
+        /// <remarks>
+        /// This property exists only for the derived <see cref="ToggleSplitButton"/> and is
+        /// unused (set to false) within <see cref="SplitButton"/>. Doing this allows the
+        /// two controls to share a default style.
+        /// </remarks>
+        internal virtual bool InternalIsChecked => false;
+
+        /// <inheritdoc/>
+        protected override bool IsEnabledCore => base.IsEnabledCore && _commandCanExecute;
+
+        ////////////////////////////////////////////////////////////////////////
+        // Methods
+        ////////////////////////////////////////////////////////////////////////
+
+        /// <inheritdoc/>
+        void ICommandSource.CanExecuteChanged(object sender, EventArgs e) => this.CanExecuteChanged(sender, e);
+
+        /// <inheritdoc cref="ICommandSource.CanExecuteChanged"/>
+        private void CanExecuteChanged(object? sender, EventArgs e)
+        {
+            var canExecute = Command == null || Command.CanExecute(CommandParameter);
+
+            if (canExecute != _commandCanExecute)
+            {
+                _commandCanExecute = canExecute;
+                UpdateIsEffectivelyEnabled();
+            }
+        }
+
+        /// <summary>
+        /// Updates the visual state of the control by applying latest PseudoClasses.
+        /// </summary>
+        protected void UpdatePseudoClasses()
+        {
+            PseudoClasses.Set(pcFlyoutOpen, _isFlyoutOpen);
+            PseudoClasses.Set(pcPressed, _isKeyboardPressed);
+            PseudoClasses.Set(pcChecked, InternalIsChecked);
+        }
+
+        /// <summary>
+        /// Opens the secondary button's flyout.
+        /// </summary>
+        protected void OpenFlyout()
+        {
+            if (Flyout != null)
+            {
+                Flyout.ShowAt(this);
+            }
+        }
+
+        /// <summary>
+        /// Closes the secondary button's flyout.
+        /// </summary>
+        protected void CloseFlyout()
+        {
+            if (Flyout != null)
+            {
+                Flyout.Hide();
+            }
+        }
+
+        /// <summary>
+        /// Registers all flyout events.
+        /// </summary>
+        /// <param name="flyout">The flyout to connect events to.</param>
+        private void RegisterFlyoutEvents(FlyoutBase? flyout)
+        {
+            if (flyout != null)
+            {
+                flyout.Opened += Flyout_Opened;
+                flyout.Closed += Flyout_Closed;
+
+                _flyoutPropertyChangedDisposable = flyout.GetPropertyChangedObservable(FlyoutBase.PlacementProperty).Subscribe(Flyout_PlacementPropertyChanged);
+            }
+        }
+
+        /// <summary>
+        /// Explicitly unregisters all flyout events.
+        /// </summary>
+        /// <param name="flyout">The flyout to disconnect events from.</param>
+        private void UnregisterFlyoutEvents(FlyoutBase? flyout)
+        {
+            if (flyout != null)
+            {
+                flyout.Opened -= Flyout_Opened;
+                flyout.Closed -= Flyout_Closed;
+
+                _flyoutPropertyChangedDisposable?.Dispose();
+                _flyoutPropertyChangedDisposable = null;
+             }
+        }
+
+        /// <summary>
+        /// Explicitly unregisters all events related to the two buttons in OnApplyTemplate().
+        /// </summary>
+        private void UnregisterEvents()
+        {
+            if (_primaryButton != null)
+            {
+                _primaryButton.Click -= PrimaryButton_Click;
+            }
+
+            if (_secondaryButton != null)
+            {
+                _secondaryButton.Click -= SecondaryButton_Click;
+            }
+        }
+
+        ////////////////////////////////////////////////////////////////////////
+        // OnEvent Overridable Methods
+        ////////////////////////////////////////////////////////////////////////
+
+        /// <inheritdoc/>
+        protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
+        {
+            UnregisterEvents();
+            UnregisterFlyoutEvents(Flyout);
+
+            _primaryButton   = e.NameScope.Find<Button>("PART_PrimaryButton");
+            _secondaryButton = e.NameScope.Find<Button>("PART_SecondaryButton");
+
+            if (_primaryButton != null)
+            {
+                _primaryButton.Click += PrimaryButton_Click;
+            }
+
+            if (_secondaryButton != null)
+            {
+                _secondaryButton.Click += SecondaryButton_Click;
+            }
+
+            RegisterFlyoutEvents(Flyout);
+            UpdatePseudoClasses();
+        }
+
+        /// <inheritdoc/>
+        protected override void OnAttachedToLogicalTree(LogicalTreeAttachmentEventArgs e)
+        {
+            base.OnAttachedToLogicalTree(e);
+
+            if (Command != null)
+            {
+                Command.CanExecuteChanged += CanExecuteChanged;
+                CanExecuteChanged(this, EventArgs.Empty);
+            }
+
+            _isAttachedToLogicalTree = true;
+        }
+
+        /// <inheritdoc/>
+        protected override void OnDetachedFromLogicalTree(LogicalTreeAttachmentEventArgs e)
+        {
+            base.OnDetachedFromLogicalTree(e);
+
+            if (Command != null)
+            {
+                Command.CanExecuteChanged -= CanExecuteChanged;
+            }
+
+            _isAttachedToLogicalTree = false;
+        }
+
+        /// <inheritdoc/>
+        protected override void OnPropertyChanged<T>(AvaloniaPropertyChangedEventArgs<T> e)
+        {
+            if (e.Property == CommandProperty)
+            {
+                if (_isAttachedToLogicalTree)
+                {
+                    // Must unregister events here while a reference to the old command still exists
+                    if (e.OldValue.GetValueOrDefault() is ICommand oldCommand)
+                    {
+                        oldCommand.CanExecuteChanged -= CanExecuteChanged;
+                    }
+
+                    if (e.NewValue.GetValueOrDefault() is ICommand newCommand)
+                    {
+                        newCommand.CanExecuteChanged += CanExecuteChanged;
+                    }
+                }
+
+                CanExecuteChanged(this, EventArgs.Empty);
+            }
+            else if (e.Property == CommandParameterProperty)
+            {
+                CanExecuteChanged(this, EventArgs.Empty);
+            }
+            else if (e.Property == FlyoutProperty)
+            {
+                var oldFlyout = e.OldValue.GetValueOrDefault() as FlyoutBase;
+                var newFlyout = e.NewValue.GetValueOrDefault() as FlyoutBase;
+
+                // If flyout is changed while one is already open, make sure we 
+                // close the old one first
+                // This is the same behavior as Button
+                if (oldFlyout != null &&
+                    oldFlyout.IsOpen)
+                {
+                    oldFlyout.Hide();
+                }
+
+                // Must unregister events here while a reference to the old flyout still exists
+                if (oldFlyout != null)
+                {
+                    UnregisterFlyoutEvents(oldFlyout);
+                }
+
+                if (newFlyout != null)
+                {
+                    RegisterFlyoutEvents(newFlyout);
+                }
+
+                UpdatePseudoClasses();
+            }
+
+            base.OnPropertyChanged(e);
+        }
+
+        /// <inheritdoc/>
+        protected override void OnKeyDown(KeyEventArgs e)
+        {
+            var key = e.Key;
+
+            if (key == Key.Space || key == Key.Enter) // Key.GamepadA is not currently supported
+            {
+                _isKeyboardPressed = true;
+                UpdatePseudoClasses();
+            }
+
+            base.OnKeyDown(e);
+        }
+
+        /// <inheritdoc/>
+        protected override void OnKeyUp(KeyEventArgs e)
+        {
+            var key = e.Key;
+
+            if (key == Key.Space || key == Key.Enter) // Key.GamepadA is not currently supported
+            {
+                _isKeyboardPressed = false;
+                UpdatePseudoClasses();
+
+                // Consider this a click on the primary button
+                if (IsEffectivelyEnabled)
+                {
+                    OnClickPrimary(null);
+                    e.Handled = true;
+                }
+            }
+            else if (key == Key.Down && e.KeyModifiers.HasAllFlags(KeyModifiers.Alt) && IsEffectivelyEnabled)
+            {
+                OpenFlyout();
+                e.Handled = true;
+            }
+            else if (key == Key.F4 && IsEffectivelyEnabled)
+            {
+                OpenFlyout();
+                e.Handled = true;
+            }
+            else if (e.Key == Key.Escape && _isFlyoutOpen)
+            {
+                // If Flyout doesn't have focusable content, close the flyout here
+                // This is the same behavior as Button
+                CloseFlyout();
+                e.Handled = true;
+            }
+
+            base.OnKeyUp(e);
+        }
+
+        /// <summary>
+        /// Invokes the <see cref="Click"/> event when the primary button part is clicked.
+        /// </summary>
+        /// <param name="e">The event args from the internal Click event.</param>
+        protected virtual void OnClickPrimary(RoutedEventArgs? e)
+        {
+            // Note: It is not currently required to check enabled status; however, this is a failsafe
+            if (IsEffectivelyEnabled)
+            {
+                var eventArgs = new RoutedEventArgs(ClickEvent);
+                RaiseEvent(eventArgs);
+
+                if (!eventArgs.Handled && Command?.CanExecute(CommandParameter) == true)
+                {
+                    Command.Execute(CommandParameter);
+                    eventArgs.Handled = true;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Invoked when the secondary button part is clicked.
+        /// </summary>
+        /// <param name="e">The event args from the internal Click event.</param>
+        protected virtual void OnClickSecondary(RoutedEventArgs? e)
+        {
+            // Note: It is not currently required to check enabled status; however, this is a failsafe
+            if (IsEffectivelyEnabled)
+            {
+                OpenFlyout();
+            }
+        }
+
+        ////////////////////////////////////////////////////////////////////////
+        // Event Handling
+        ////////////////////////////////////////////////////////////////////////
+
+        /// <summary>
+        /// Event handler for when the internal primary button part is pressed.
+        /// </summary>
+        private void PrimaryButton_Click(object? sender, RoutedEventArgs e)
+        {
+            // Handle internal button click, so it won't bubble outside together with SplitButton.ClickEvent.
+            e.Handled = true;
+            OnClickPrimary(e);
+        }
+
+        /// <summary>
+        /// Event handler for when the internal secondary button part is pressed.
+        /// </summary>
+        private void SecondaryButton_Click(object? sender, RoutedEventArgs e)
+        {
+            // Handle internal button click, so it won't bubble outside.
+            e.Handled = true;
+            OnClickSecondary(e);
+        }
+
+        /// <summary>
+        /// Called when the <see cref="FlyoutBase.Placement"/> property changes.
+        /// </summary>
+        private void Flyout_PlacementPropertyChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            UpdatePseudoClasses();
+        }
+
+        /// <summary>
+        /// Event handler for when the split button's flyout is opened.
+        /// </summary>
+        private void Flyout_Opened(object? sender, EventArgs e)
+        {
+            var flyout = sender as FlyoutBase;
+
+            // It is possible to share flyouts among multiple controls including SplitButton.
+            // This can cause a problem here since all controls that share a flyout receive
+            // the same Opened/Closed events at the same time.
+            // For SplitButton that means they all would be updating their pseudoclasses accordingly.
+            // In other words, all SplitButtons with a shared Flyout would have the backgrounds changed together.
+            // To fix this, only continue here if the Flyout target matches this SplitButton instance.
+            if (object.ReferenceEquals(flyout?.Target, this))
+            {
+                _isFlyoutOpen = true;
+                UpdatePseudoClasses();
+            }
+        }
+
+        /// <summary>
+        /// Event handler for when the split button's flyout is closed.
+        /// </summary>
+        private void Flyout_Closed(object? sender, EventArgs e)
+        {
+            var flyout = sender as FlyoutBase;
+
+            // See comments in Flyout_Opened
+            if (object.ReferenceEquals(flyout?.Target, this))
+            {
+                _isFlyoutOpen = false;
+                UpdatePseudoClasses();
+            }
+        }
+    }
+}

src/Avalonia.Controls/SplitButton/ToggleSplitButton.cs

@@ -0,0 +1,125 @@
+using System;
+
+using Avalonia.Controls.Metadata;
+using Avalonia.Controls.Primitives;
+using Avalonia.Interactivity;
+using Avalonia.Styling;
+
+namespace Avalonia.Controls
+{
+    /// <summary>
+    /// A button with primary and secondary parts that can each be pressed separately.
+    /// The primary part behaves like a <see cref="ToggleButton"/> with two states and
+    /// the secondary part opens a flyout.
+    /// </summary>
+    [PseudoClasses(pcChecked)]
+    public class ToggleSplitButton : SplitButton, IStyleable
+    {
+        /// <summary>
+        /// Raised when the <see cref="IsChecked"/> property value changes.
+        /// </summary>
+        public event EventHandler<RoutedEventArgs> IsCheckedChanged
+        {
+            add => AddHandler(IsCheckedChangedEvent, value);
+            remove => RemoveHandler(IsCheckedChangedEvent, value);
+        }
+
+        /// <summary>
+        /// Defines the <see cref="IsCheckedChanged"/> event.
+        /// </summary>
+        public static readonly RoutedEvent<RoutedEventArgs> IsCheckedChangedEvent =
+            RoutedEvent.Register<ToggleSplitButton, RoutedEventArgs>(
+                nameof(IsCheckedChanged),
+                RoutingStrategies.Bubble);
+
+        /// <summary>
+        /// Defines the <see cref="IsChecked"/> property.
+        /// </summary>
+        public static readonly StyledProperty<bool> IsCheckedProperty =
+            AvaloniaProperty.Register<ToggleSplitButton, bool>(
+                nameof(IsChecked));
+
+        ////////////////////////////////////////////////////////////////////////
+        // Constructor / Destructors
+        ////////////////////////////////////////////////////////////////////////
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ToggleSplitButton"/> class.
+        /// </summary>
+        public ToggleSplitButton()
+        {
+        }
+
+        ////////////////////////////////////////////////////////////////////////
+        // Properties
+        ////////////////////////////////////////////////////////////////////////
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the <see cref="ToggleSplitButton"/> is checked.
+        /// </summary>
+        public bool IsChecked
+        {
+            get => GetValue(IsCheckedProperty);
+            set => SetValue(IsCheckedProperty, value);
+        }
+
+        /// <inheritdoc/>
+        internal override bool InternalIsChecked => IsChecked;
+
+        /// <inheritdoc/>
+        /// <remarks>
+        /// Both <see cref="ToggleSplitButton"/> and <see cref="SplitButton"/> share
+        /// the same exact default style.
+        /// </remarks>
+        Type IStyleable.StyleKey => typeof(SplitButton);
+
+        ////////////////////////////////////////////////////////////////////////
+        // Methods
+        ////////////////////////////////////////////////////////////////////////
+
+        /// <summary>
+        /// Toggles the <see cref="IsChecked"/> property between true and false.
+        /// </summary>
+        protected void Toggle()
+        {
+            IsChecked = !IsChecked;
+        }
+
+        ////////////////////////////////////////////////////////////////////////
+        // OnEvent Overridable Methods
+        ////////////////////////////////////////////////////////////////////////
+
+        /// <inheritdoc/>
+        protected override void OnPropertyChanged<T>(AvaloniaPropertyChangedEventArgs<T> e)
+        {
+            if (e.Property == IsCheckedProperty)
+            {
+                OnIsCheckedChanged();
+            }
+        }
+
+        /// <summary>
+        /// Invokes the <see cref="IsCheckedChanged"/> event when the <see cref="IsChecked"/>
+        /// property changes.
+        /// </summary>
+        protected virtual void OnIsCheckedChanged()
+        {
+            // IsLoaded check
+            if (Parent is not null)
+            {
+                var eventArgs = new RoutedEventArgs(IsCheckedChangedEvent);
+                RaiseEvent(eventArgs);
+            }
+
+            UpdatePseudoClasses();
+        }
+
+        /// <inheritdoc/>
+        protected override void OnClickPrimary(RoutedEventArgs? e)
+        {
+            Toggle();
+
+            base.OnClickPrimary(e);
+        }
+    }
+}

src/Avalonia.Input/ICommandSource.cs

@@ -20,12 +20,11 @@ namespace Avalonia.Input
         /// </summary>
         object? CommandParameter { get; }
 
-
         /// <summary>
-        /// Bor the behavior CanExecuteChanged
+        /// Called for the CanExecuteChanged event when changes are detected.
         /// </summary>
-        /// <param name="sender"></param>
-        /// <param name="e"></param>
+        /// <param name="sender">The event sender.</param>
+        /// <param name="e">The event args.</param>
         void CanExecuteChanged(object sender, System.EventArgs e);
 
         /// <summary>

src/Avalonia.Themes.Default/Controls/SplitButton.xaml

@@ -0,0 +1,271 @@
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        x:CompileBindings="True"
+        xmlns:converters="using:Avalonia.Controls.Converters">
+
+  <!-- This style is heavily based on the Fluent v1 style.
+       The base resources are switched out along with a few minor changes such as Padding, CornerRadius. -->
+
+  <Design.PreviewWith>
+    <Border Padding="20">
+      <SplitButton />
+    </Border>
+  </Design.PreviewWith>
+
+  <Styles.Resources>
+    <x:Double x:Key="SplitButtonPrimaryButtonSize">24</x:Double>
+    <x:Double x:Key="SplitButtonSecondaryButtonSize">24</x:Double>
+    <x:Double x:Key="SplitButtonSeparatorWidth">1</x:Double>
+    <Thickness x:Key="SplitButtonBorderThemeThickness">1</Thickness>
+
+    <converters:MarginMultiplierConverter x:Key="PrimaryButtonBorderMultiplier" Left="True" Top="True" Bottom="True" Indent="1" />
+    <converters:MarginMultiplierConverter x:Key="SecondaryButtonBorderMultiplier" Right="True" Top="True" Bottom="True" Indent="1" />
+    <converters:MarginMultiplierConverter x:Key="SeparatorBorderMultiplier" Top="True" Bottom="True" Indent="1" />
+    <converters:CornerRadiusFilterConverter x:Key="TopCornerRadiusFilterConverter" Filter="TopLeft, TopRight"/>
+    <converters:CornerRadiusFilterConverter x:Key="RightCornerRadiusFilterConverter" Filter="TopRight, BottomRight"/>
+    <converters:CornerRadiusFilterConverter x:Key="BottomCornerRadiusFilterConverter" Filter="BottomLeft, BottomRight"/>
+    <converters:CornerRadiusFilterConverter x:Key="LeftCornerRadiusFilterConverter" Filter="TopLeft, BottomLeft"/>
+
+    <SolidColorBrush x:Key="SplitButtonBackground" Color="{DynamicResource ThemeControlMidColor}" />
+    <SolidColorBrush x:Key="SplitButtonBackgroundPointerOver" Color="{DynamicResource ThemeControlMidColor}" />
+    <SolidColorBrush x:Key="SplitButtonBackgroundPressed" Color="{DynamicResource ThemeBorderHighColor}" />
+    <SolidColorBrush x:Key="SplitButtonBackgroundDisabled" Color="{DynamicResource ThemeControlMidColor}" Opacity="{DynamicResource ThemeDisabledOpacity}" />
+    <SolidColorBrush x:Key="SplitButtonBackgroundChecked" Color="{DynamicResource ThemeBorderHighColor}" />
+    <SolidColorBrush x:Key="SplitButtonBackgroundCheckedPointerOver" Color="{DynamicResource ThemeBorderHighColor}" />
+    <SolidColorBrush x:Key="SplitButtonBackgroundCheckedPressed" Color="{DynamicResource ThemeBorderHighColor}" />
+    <SolidColorBrush x:Key="SplitButtonBackgroundCheckedDisabled" Color="{DynamicResource ThemeControlHighColor}" Opacity="{DynamicResource ThemeDisabledOpacity}" />
+
+    <SolidColorBrush x:Key="SplitButtonForeground" Color="{DynamicResource ThemeForegroundColor}" />
+    <SolidColorBrush x:Key="SplitButtonForegroundPointerOver" Color="{DynamicResource ThemeForegroundColor}" />
+    <SolidColorBrush x:Key="SplitButtonForegroundPressed" Color="{DynamicResource ThemeForegroundColor}" />
+    <SolidColorBrush x:Key="SplitButtonForegroundDisabled" Color="{DynamicResource ThemeForegroundColor}" />
+    <SolidColorBrush x:Key="SplitButtonForegroundChecked" Color="{DynamicResource ThemeForegroundColor}" />
+    <SolidColorBrush x:Key="SplitButtonForegroundCheckedPointerOver" Color="{DynamicResource ThemeForegroundColor}" />
+    <SolidColorBrush x:Key="SplitButtonForegroundCheckedPressed" Color="{DynamicResource ThemeForegroundColor}" />
+    <SolidColorBrush x:Key="SplitButtonForegroundCheckedDisabled" Color="{DynamicResource ThemeForegroundColor}" />
+
+    <SolidColorBrush x:Key="SplitButtonBorderBrush" Color="{DynamicResource ThemeBorderLowColor}" />
+    <SolidColorBrush x:Key="SplitButtonBorderBrushPointerOver" Color="{DynamicResource ThemeBorderMidColor}" />
+    <SolidColorBrush x:Key="SplitButtonBorderBrushPressed" Color="{DynamicResource ThemeBorderLowColor}" />
+    <SolidColorBrush x:Key="SplitButtonBorderBrushDisabled" Color="{DynamicResource ThemeBorderLowColor}" />
+    <SolidColorBrush x:Key="SplitButtonBorderBrushChecked" Color="{DynamicResource ThemeBorderMidColor}" />
+    <SolidColorBrush x:Key="SplitButtonBorderBrushCheckedPointerOver" Color="{DynamicResource ThemeBorderMidColor}" />
+    <SolidColorBrush x:Key="SplitButtonBorderBrushCheckedPressed" Color="{DynamicResource ThemeControlHighColor}" />
+    <SolidColorBrush x:Key="SplitButtonBorderBrushCheckedDisabled" Color="{DynamicResource ThemeControlMidColor}" Opacity="{DynamicResource ThemeDisabledOpacity}" />
+  </Styles.Resources>
+
+  <Style Selector="SplitButton">
+    <Setter Property="Background" Value="{DynamicResource SplitButtonBackground}" />
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForeground}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource SplitButtonBorderBrush}" />
+    <Setter Property="BorderThickness" Value="{DynamicResource SplitButtonBorderThemeThickness}" />
+    <Setter Property="HorizontalAlignment" Value="Left" />
+    <Setter Property="VerticalAlignment" Value="Center" />
+    <!--<Setter Property="UseSystemFocusVisuals" Value="True" />
+    <Setter Property="FocusVisualMargin" Value="-3" />-->
+    <Setter Property="KeyboardNavigation.IsTabStop" Value="True" />
+    <Setter Property="Focusable" Value="True" />
+    <Setter Property="Padding" Value="4" />
+    <Setter Property="CornerRadius" Value="0" />
+    <Setter Property="Template">
+      <Setter.Value>
+        <ControlTemplate>
+          <Grid>
+            <Grid.ColumnDefinitions>
+              <ColumnDefinition Width="*" />
+              <ColumnDefinition Width="Auto" />
+              <ColumnDefinition Width="Auto" />
+            </Grid.ColumnDefinitions>
+
+            <Button x:Name="PART_PrimaryButton"
+                    Grid.Column="0"
+                    MinWidth="{DynamicResource SplitButtonPrimaryButtonSize}"
+                    Foreground="{TemplateBinding Foreground}"
+                    Background="{TemplateBinding Background}"
+                    BorderThickness="{TemplateBinding BorderThickness, Converter={StaticResource PrimaryButtonBorderMultiplier}}"
+                    BorderBrush="{TemplateBinding BorderBrush}"
+                    Content="{TemplateBinding Content}"
+                    ContentTemplate="{TemplateBinding ContentTemplate}"
+                    Command="{TemplateBinding Command}"
+                    CommandParameter="{TemplateBinding CommandParameter}"
+                    FontFamily="{TemplateBinding FontFamily}"
+                    FontSize="{TemplateBinding FontSize}"
+                    FontWeight="{TemplateBinding FontWeight}"
+                    HorizontalAlignment="Stretch"
+                    VerticalAlignment="Stretch"
+                    HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
+                    VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
+                    Padding="{TemplateBinding Padding}"
+                    Focusable="False"
+                    KeyboardNavigation.IsTabStop="False" />
+
+            <Border x:Name="SeparatorBorder"
+                    Grid.Column="1"
+                    Background="Transparent"
+                    Width="{DynamicResource SplitButtonSeparatorWidth}"
+                    BorderThickness="{TemplateBinding BorderThickness, Converter={StaticResource SeparatorBorderMultiplier}}"
+                    BorderBrush="{TemplateBinding BorderBrush}" />
+
+            <Button x:Name="PART_SecondaryButton"
+                    Grid.Column="2"
+                    MinWidth="{DynamicResource SplitButtonSecondaryButtonSize}"
+                    BorderBrush="{TemplateBinding BorderBrush}"
+                    Foreground="{TemplateBinding Foreground}"
+                    Background="{TemplateBinding Background}"
+                    BorderThickness="{TemplateBinding BorderThickness, Converter={StaticResource SecondaryButtonBorderMultiplier}}"
+                    Padding="0"
+                    HorizontalContentAlignment="Center"
+                    VerticalContentAlignment="Center"
+                    HorizontalAlignment="Stretch"
+                    VerticalAlignment="Stretch"
+                    Focusable="False"
+                    KeyboardNavigation.IsTabStop="False" />
+          </Grid>
+        </ControlTemplate>
+      </Setter.Value>
+    </Setter>
+  </Style>
+
+  <!-- Default overridable styles -->
+  <Style Selector="SplitButton /template/ Button#PART_PrimaryButton">
+    <Setter Property="CornerRadius" Value="{TemplateBinding CornerRadius, Converter={StaticResource LeftCornerRadiusFilterConverter}}" />
+  </Style>
+  <Style Selector="SplitButton /template/ Button#PART_SecondaryButton">
+    <Setter Property="CornerRadius" Value="{TemplateBinding CornerRadius, Converter={StaticResource RightCornerRadiusFilterConverter}}" />
+    <Setter Property="Content">
+      <Template>
+        <PathIcon Height="12"
+                  Width="12"
+                  Data="M1939 486L2029 576L1024 1581L19 576L109 486L1024 1401L1939 486Z" />
+      </Template>
+    </Setter>
+  </Style>
+
+  <!-- Primary and Secondary buttons PointerOver State -->
+  <Style Selector="SplitButton /template/ Button#PART_PrimaryButton:pointerover /template/ ContentPresenter,
+         SplitButton /template/ Button#PART_SecondaryButton:pointerover /template/ ContentPresenter">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundPointerOver}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushPointerOver}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundPointerOver}" />
+  </Style>
+  <Style Selector="SplitButton /template/ Button#PART_SecondaryButton:pointerover PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundPointerOver}" />
+  </Style>
+
+  <!-- Primary and Secondary buttons Pressed State -->
+  <Style Selector="SplitButton /template/ Button#PART_PrimaryButton:pressed /template/ ContentPresenter,
+         SplitButton /template/ Button#PART_SecondaryButton:pressed /template/ ContentPresenter">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+  <Style Selector="SplitButton /template/ Button#PART_SecondaryButton:pressed PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+
+  <!-- SplitButton Pressed State -->
+  <Style Selector="SplitButton:pressed /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:pressed /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:pressed /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+  <Style Selector="SplitButton:pressed /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+
+  <!-- Primary and Secondary buttons Flyout Open State -->
+  <Style Selector="SplitButton:flyout-open /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:flyout-open /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:flyout-open /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+  <Style Selector="SplitButton:flyout-open /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+
+  <!-- Disabled State -->
+  <Style Selector="SplitButton:disabled /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:disabled /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:disabled /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundDisabled}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushDisabled}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundDisabled}" />
+  </Style>
+  <Style Selector="SplitButton:disabled /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundDisabled}" />
+  </Style>
+
+  <!-- Checked State -->
+  <Style Selector="SplitButton:checked /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:checked /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:checked /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundChecked}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushChecked}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundChecked}" />
+  </Style>
+  <Style Selector="SplitButton:checked /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundChecked}" />
+  </Style>
+
+  <!-- Checked PointerOver State -->
+  <Style Selector="SplitButton:checked /template/ Button#PART_PrimaryButton:pointerover /template/ ContentPresenter,
+         SplitButton:checked /template/ Button#PART_SecondaryButton:pointerover /template/ ContentPresenter">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundCheckedPointerOver}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushCheckedPointerOver}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPointerOver}" />
+  </Style>
+  <Style Selector="SplitButton:checked /template/ Button#PART_SecondaryButton:pointerover PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPointerOver}" />
+  </Style>
+
+  <!-- Checked Pressed State -->
+  <Style Selector="SplitButton:checked /template/ Button#PART_PrimaryButton:pressed /template/ ContentPresenter,
+         SplitButton:checked /template/ Button#PART_SecondaryButton:pressed /template/ ContentPresenter">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundCheckedPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushCheckedPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+  <Style Selector="SplitButton:checked /template/ Button#PART_SecondaryButton:pressed PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+
+  <!-- SplitButton Checked Pressed State -->
+  <Style Selector="SplitButton:pressed:checked /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:pressed:checked /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:pressed:checked /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundCheckedPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushCheckedPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+  <Style Selector="SplitButton:pressed:checked /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+
+  <!-- Checked Flyout Open State -->
+  <Style Selector="SplitButton:checked:flyout-open /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:checked:flyout-open /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:checked:flyout-open /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundCheckedPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushCheckedPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+  <Style Selector="SplitButton:checked:flyout-open /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+
+  <!-- Disabled Checked State -->
+  <Style Selector="SplitButton:checked:disabled /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:checked:disabled /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:checked:disabled /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundCheckedDisabled}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushCheckedDisabled}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundCheckedDisabled}" />
+  </Style>
+  <Style Selector="SplitButton:checked:disabled /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundCheckedDisabled}" />
+  </Style>
+</Styles>

src/Avalonia.Themes.Default/DefaultTheme.xaml

@@ -57,6 +57,7 @@
   <StyleInclude Source="avares://Avalonia.Themes.Default/Controls/NotificationCard.xaml"/>
   <StyleInclude Source="avares://Avalonia.Themes.Default/Controls/NativeMenuBar.xaml"/>
   <StyleInclude Source="avares://Avalonia.Themes.Default/Controls/ToggleSwitch.xaml"/>
+  <StyleInclude Source="avares://Avalonia.Themes.Default/Controls/SplitButton.xaml" />
   <StyleInclude Source="avares://Avalonia.Themes.Default/Controls/SplitView.xaml"/>
   <StyleInclude Source="avares://Avalonia.Themes.Default/Controls/DatePicker.xaml"/>
   <StyleInclude Source="avares://Avalonia.Themes.Default/Controls/TimePicker.xaml"/>

src/Avalonia.Themes.Fluent/Accents/FluentControlResourcesDark.xaml

@@ -556,6 +556,33 @@
     <Thickness x:Key="TreeViewItemBorderThemeThickness">1</Thickness>
     <x:Double x:Key="TreeViewItemMinHeight">32</x:Double>
 
+    <!-- Resources for SplitButton.xaml (shared with ToggleSplitButton) -->
+    <StaticResource x:Key="SplitButtonBackground" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <SolidColorBrush x:Key="SplitButtonBackgroundPointerOver" Color="{StaticResource SystemBaseHighColor}" Opacity="0.1" />
+    <StaticResource x:Key="SplitButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="SplitButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="SplitButtonBackgroundChecked" ResourceKey="SystemControlHighlightAccentBrush" />
+    <StaticResource x:Key="SplitButtonBackgroundCheckedPointerOver" ResourceKey="SystemAccentColorDark1" />
+    <StaticResource x:Key="SplitButtonBackgroundCheckedPressed" ResourceKey="SystemAccentColorLight1" />
+    <StaticResource x:Key="SplitButtonBackgroundCheckedDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="SplitButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="SplitButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="SplitButtonForegroundPressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="SplitButtonForegroundDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="SplitButtonForegroundChecked" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="SplitButtonForegroundCheckedPointerOver" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="SplitButtonForegroundCheckedPressed" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="SplitButtonForegroundCheckedDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrush" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushPointerOver" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushChecked" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushCheckedPointerOver" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushCheckedPressed" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushCheckedDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <Thickness x:Key="SplitButtonBorderThemeThickness">1</Thickness>
+
     <!-- Resources for SplitView.xaml -->
     <StaticResource x:Key="SplitViewLightDismissOverlayBackground" ResourceKey="SystemControlPageBackgroundMediumAltMediumBrush" />
   

src/Avalonia.Themes.Fluent/Accents/FluentControlResourcesLight.xaml

@@ -550,6 +550,33 @@
     <Thickness x:Key="TreeViewItemBorderThemeThickness">1</Thickness>
     <x:Double x:Key="TreeViewItemMinHeight">32</x:Double>
 
+    <!-- Resources for SplitButton.xaml (shared with ToggleSplitButton) -->
+    <StaticResource x:Key="SplitButtonBackground" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <SolidColorBrush x:Key="SplitButtonBackgroundPointerOver" Color="{StaticResource SystemBaseHighColor}" Opacity="0.1" />
+    <StaticResource x:Key="SplitButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
+    <StaticResource x:Key="SplitButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="SplitButtonBackgroundChecked" ResourceKey="SystemControlHighlightAccentBrush" />
+    <StaticResource x:Key="SplitButtonBackgroundCheckedPointerOver" ResourceKey="SystemAccentColorLight1" />
+    <StaticResource x:Key="SplitButtonBackgroundCheckedPressed" ResourceKey="SystemAccentColorDark1" />
+    <StaticResource x:Key="SplitButtonBackgroundCheckedDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
+    <StaticResource x:Key="SplitButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="SplitButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="SplitButtonForegroundPressed" ResourceKey="SystemControlHighlightBaseHighBrush" />
+    <StaticResource x:Key="SplitButtonForegroundDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="SplitButtonForegroundChecked" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="SplitButtonForegroundCheckedPointerOver" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="SplitButtonForegroundCheckedPressed" ResourceKey="SystemControlHighlightAltChromeWhiteBrush" />
+    <StaticResource x:Key="SplitButtonForegroundCheckedDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrush" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushPointerOver" ResourceKey="SystemControlForegroundTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushPressed" ResourceKey="SystemControlHighlightTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushChecked" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushCheckedPointerOver" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushCheckedPressed" ResourceKey="SystemControlHighlightAltTransparentBrush" />
+    <StaticResource x:Key="SplitButtonBorderBrushCheckedDisabled" ResourceKey="SystemControlDisabledTransparentBrush" />
+    <Thickness x:Key="SplitButtonBorderThemeThickness">1</Thickness>
+
     <!-- Resources for SplitView.xaml -->
     <StaticResource x:Key="SplitViewLightDismissOverlayBackground" ResourceKey="SystemControlPageBackgroundMediumAltMediumBrush" />
   

src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml

@@ -150,7 +150,7 @@
     </Setter>
   </Style>
 
-  <!--  NormalState  -->
+  <!--  Normal State  -->
   <Style Selector="ComboBox /template/ TextBlock#PlaceholderTextBlock">
     <Setter Property="Foreground" Value="{DynamicResource ComboBoxPlaceHolderForeground}" />
   </Style>

src/Avalonia.Themes.Fluent/Controls/FluentControls.xaml

@@ -56,6 +56,7 @@
   <StyleInclude Source="avares://Avalonia.Themes.Fluent/Controls/NotificationCard.xaml"/>
   <StyleInclude Source="avares://Avalonia.Themes.Fluent/Controls/NativeMenuBar.xaml"/>
   <StyleInclude Source="avares://Avalonia.Themes.Fluent/Controls/ToggleSwitch.xaml"/>
+  <StyleInclude Source="avares://Avalonia.Themes.Fluent/Controls/SplitButton.xaml" />
   <StyleInclude Source="avares://Avalonia.Themes.Fluent/Controls/SplitView.xaml"/>
   <StyleInclude Source="avares://Avalonia.Themes.Fluent/Controls/DatePicker.xaml"/>  
   <StyleInclude Source="avares://Avalonia.Themes.Fluent/Controls/TimePicker.xaml"/>  

src/Avalonia.Themes.Fluent/Controls/SplitButton.xaml

@@ -0,0 +1,247 @@
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        x:CompileBindings="True"
+        xmlns:converters="using:Avalonia.Controls.Converters">
+
+  <Design.PreviewWith>
+    <Border Padding="60">
+      <StackPanel>
+        <SplitButton Content="Hello World">
+          <SplitButton.Flyout>
+            <Flyout>Hello</Flyout>
+          </SplitButton.Flyout>
+        </SplitButton>
+        <ToggleSplitButton Content="Hello World">
+          <ToggleSplitButton.Flyout>
+            <Flyout>Hello</Flyout>
+          </ToggleSplitButton.Flyout>
+        </ToggleSplitButton>
+      </StackPanel>
+    </Border>
+  </Design.PreviewWith>
+
+  <Styles.Resources>
+    <x:Double x:Key="SplitButtonPrimaryButtonSize">32</x:Double>
+    <x:Double x:Key="SplitButtonSecondaryButtonSize">32</x:Double>
+    <x:Double x:Key="SplitButtonSeparatorWidth">1</x:Double>
+
+    <converters:MarginMultiplierConverter x:Key="PrimaryButtonBorderMultiplier" Left="True" Top="True" Bottom="True" Indent="1" />
+    <converters:MarginMultiplierConverter x:Key="SecondaryButtonBorderMultiplier" Right="True" Top="True" Bottom="True" Indent="1" />
+    <converters:MarginMultiplierConverter x:Key="SeparatorBorderMultiplier" Top="True" Bottom="True" Indent="1" />
+  </Styles.Resources>
+
+  <Style Selector="SplitButton">
+    <Setter Property="Background" Value="{DynamicResource SplitButtonBackground}" />
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForeground}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource SplitButtonBorderBrush}" />
+    <Setter Property="BorderThickness" Value="{DynamicResource SplitButtonBorderThemeThickness}" />
+    <Setter Property="HorizontalAlignment" Value="Left" />
+    <Setter Property="VerticalAlignment" Value="Center" />
+    <!--<Setter Property="UseSystemFocusVisuals" Value="True" />
+    <Setter Property="FocusVisualMargin" Value="-3" />-->
+    <Setter Property="KeyboardNavigation.IsTabStop" Value="True" />
+    <Setter Property="Focusable" Value="True" />
+    <Setter Property="Padding" Value="{DynamicResource ButtonPadding}" />
+    <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
+    <Setter Property="Template">
+      <Setter.Value>
+        <ControlTemplate>
+          <Grid>
+            <Grid.ColumnDefinitions>
+              <ColumnDefinition Width="*" />
+              <ColumnDefinition Width="Auto" />
+              <ColumnDefinition Width="Auto" />
+            </Grid.ColumnDefinitions>
+
+            <Button x:Name="PART_PrimaryButton"
+                    Grid.Column="0"
+                    MinWidth="{DynamicResource SplitButtonPrimaryButtonSize}"
+                    Foreground="{TemplateBinding Foreground}"
+                    Background="{TemplateBinding Background}"
+                    BorderThickness="{TemplateBinding BorderThickness, Converter={StaticResource PrimaryButtonBorderMultiplier}}"
+                    BorderBrush="{TemplateBinding BorderBrush}"
+                    Content="{TemplateBinding Content}"
+                    ContentTemplate="{TemplateBinding ContentTemplate}"
+                    Command="{TemplateBinding Command}"
+                    CommandParameter="{TemplateBinding CommandParameter}"
+                    FontFamily="{TemplateBinding FontFamily}"
+                    FontSize="{TemplateBinding FontSize}"
+                    FontWeight="{TemplateBinding FontWeight}"
+                    HorizontalAlignment="Stretch"
+                    VerticalAlignment="Stretch"
+                    HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
+                    VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
+                    Padding="{TemplateBinding Padding}"
+                    Focusable="False"
+                    KeyboardNavigation.IsTabStop="False" />
+
+            <Border x:Name="SeparatorBorder"
+                    Grid.Column="1"
+                    Background="Transparent"
+                    Width="{DynamicResource SplitButtonSeparatorWidth}"
+                    BorderThickness="{TemplateBinding BorderThickness, Converter={StaticResource SeparatorBorderMultiplier}}"
+                    BorderBrush="{TemplateBinding BorderBrush}" />
+
+            <Button x:Name="PART_SecondaryButton"
+                    Grid.Column="2"
+                    MinWidth="{DynamicResource SplitButtonSecondaryButtonSize}"
+                    BorderBrush="{TemplateBinding BorderBrush}"
+                    Foreground="{TemplateBinding Foreground}"
+                    Background="{TemplateBinding Background}"
+                    BorderThickness="{TemplateBinding BorderThickness, Converter={StaticResource SecondaryButtonBorderMultiplier}}"
+                    Padding="0"
+                    HorizontalContentAlignment="Center"
+                    VerticalContentAlignment="Center"
+                    HorizontalAlignment="Stretch"
+                    VerticalAlignment="Stretch"
+                    Focusable="False"
+                    KeyboardNavigation.IsTabStop="False" />
+          </Grid>
+        </ControlTemplate>
+      </Setter.Value>
+    </Setter>
+  </Style>
+
+  <!-- Default overridable styles -->
+  <Style Selector="SplitButton /template/ Button#PART_PrimaryButton">
+    <Setter Property="CornerRadius" Value="{TemplateBinding CornerRadius, Converter={StaticResource LeftCornerRadiusFilterConverter}}" />
+  </Style>
+  <Style Selector="SplitButton /template/ Button#PART_SecondaryButton">
+    <Setter Property="CornerRadius" Value="{TemplateBinding CornerRadius, Converter={StaticResource RightCornerRadiusFilterConverter}}" />
+    <Setter Property="Content">
+      <Template>
+        <PathIcon Height="12"
+                  Width="12"
+                  Data="M1939 486L2029 576L1024 1581L19 576L109 486L1024 1401L1939 486Z" />
+      </Template>
+    </Setter>
+  </Style>
+
+  <!-- Primary and Secondary buttons PointerOver State -->
+  <Style Selector="SplitButton /template/ Button#PART_PrimaryButton:pointerover /template/ ContentPresenter,
+         SplitButton /template/ Button#PART_SecondaryButton:pointerover /template/ ContentPresenter">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundPointerOver}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushPointerOver}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundPointerOver}" />
+  </Style>
+  <Style Selector="SplitButton /template/ Button#PART_SecondaryButton:pointerover PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundPointerOver}" />
+  </Style>
+
+  <!-- Primary and Secondary buttons Pressed State -->
+  <Style Selector="SplitButton /template/ Button#PART_PrimaryButton:pressed /template/ ContentPresenter,
+         SplitButton /template/ Button#PART_SecondaryButton:pressed /template/ ContentPresenter">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+  <Style Selector="SplitButton /template/ Button#PART_SecondaryButton:pressed PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+
+  <!-- SplitButton Pressed State -->
+  <Style Selector="SplitButton:pressed /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:pressed /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:pressed /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+  <Style Selector="SplitButton:pressed /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+
+  <!-- Primary and Secondary buttons Flyout Open State -->
+  <Style Selector="SplitButton:flyout-open /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:flyout-open /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:flyout-open /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+  <Style Selector="SplitButton:flyout-open /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundPressed}" />
+  </Style>
+
+  <!-- Disabled State -->
+  <Style Selector="SplitButton:disabled /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:disabled /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:disabled /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundDisabled}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushDisabled}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundDisabled}" />
+  </Style>
+  <Style Selector="SplitButton:disabled /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundDisabled}" />
+  </Style>
+
+  <!-- Checked State -->
+  <Style Selector="SplitButton:checked /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:checked /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:checked /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundChecked}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushChecked}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundChecked}" />
+  </Style>
+  <Style Selector="SplitButton:checked /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundChecked}" />
+  </Style>
+
+  <!-- Checked PointerOver State -->
+  <Style Selector="SplitButton:checked /template/ Button#PART_PrimaryButton:pointerover /template/ ContentPresenter,
+         SplitButton:checked /template/ Button#PART_SecondaryButton:pointerover /template/ ContentPresenter">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundCheckedPointerOver}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushCheckedPointerOver}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPointerOver}" />
+  </Style>
+  <Style Selector="SplitButton:checked /template/ Button#PART_SecondaryButton:pointerover PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPointerOver}" />
+  </Style>
+
+  <!-- Checked Pressed State -->
+  <Style Selector="SplitButton:checked /template/ Button#PART_PrimaryButton:pressed /template/ ContentPresenter,
+         SplitButton:checked /template/ Button#PART_SecondaryButton:pressed /template/ ContentPresenter">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundCheckedPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushCheckedPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+  <Style Selector="SplitButton:checked /template/ Button#PART_SecondaryButton:pressed PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+
+  <!-- SplitButton Checked Pressed State -->
+  <Style Selector="SplitButton:pressed:checked /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:pressed:checked /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:pressed:checked /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundCheckedPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushCheckedPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+  <Style Selector="SplitButton:pressed:checked /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+
+  <!-- Checked Flyout Open State -->
+  <Style Selector="SplitButton:checked:flyout-open /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:checked:flyout-open /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:checked:flyout-open /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundCheckedPressed}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushCheckedPressed}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+  <Style Selector="SplitButton:checked:flyout-open /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundCheckedPressed}" />
+  </Style>
+
+  <!-- Disabled Checked State -->
+  <Style Selector="SplitButton:checked:disabled /template/ Button#PART_PrimaryButton /template/ ContentPresenter,
+         SplitButton:checked:disabled /template/ Button#PART_SecondaryButton /template/ ContentPresenter,
+         SplitButton:checked:disabled /template/ Border#SeparatorBorder">
+    <Setter Property="Border.Background" Value="{DynamicResource SplitButtonBackgroundCheckedDisabled}" />
+    <Setter Property="Border.BorderBrush" Value="{DynamicResource SplitButtonBorderBrushCheckedDisabled}" />
+    <Setter Property="TextBlock.Foreground" Value="{DynamicResource SplitButtonForegroundCheckedDisabled}" />
+  </Style>
+  <Style Selector="SplitButton:checked:disabled /template/ Button#PART_SecondaryButton PathIcon">
+    <Setter Property="Foreground" Value="{DynamicResource SplitButtonForegroundCheckedDisabled}" />
+  </Style>
+</Styles>