completed the branch

README.md

@@ -48,6 +48,10 @@ Step 3：enjoy coding
 
 ## Latest examples
 
+### SideMenu
+
+![SideMenu](https://raw.githubusercontent.com/NaBian/HandyControl/master/Resources/SideMenu.png)
+
 ### NotifyIcon
 
 ![NotifyIcon](https://raw.githubusercontent.com/NaBian/HandyControl/master/Resources/NotifyIcon.png)
@@ -64,12 +68,12 @@ Step 3：enjoy coding
 
 ![Badge](https://raw.githubusercontent.com/NaBian/HandyControl/master/Resources/Badge.png)
 
+## History publication
+
 ### Gravatar
 
 ![Gravatar](https://raw.githubusercontent.com/NaBian/HandyControl/master/Resources/Gravatar.gif)
 
-## History publication
-
 ### GoToTop
 
 ![GoToTop](https://raw.githubusercontent.com/NaBian/HandyControl/master/Resources/GoToTop.gif)

src/Core_30/HandyControlDemo_Core_30/HandyControlDemo_Core30.csproj

@@ -321,6 +321,30 @@
     <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\under_construction.gif">
       <Link>Resources\Img\under_construction.gif</Link>
     </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\DevOps\DevOps-Boards.png">
+      <Link>Resources\Img\DevOps\DevOps-Boards.png</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\DevOps\DevOps-Overview.png">
+      <Link>Resources\Img\DevOps\DevOps-Overview.png</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\DevOps\DevOps-Pipelines.png">
+      <Link>Resources\Img\DevOps\DevOps-Pipelines.png</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\DevOps\DevOps-Repos.png">
+      <Link>Resources\Img\DevOps\DevOps-Repos.png</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\DevOps\DevOps-TestPlans.png">
+      <Link>Resources\Img\DevOps\DevOps-TestPlans.png</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\LeftMainContent\MainMenuControl_16x.png">
+      <Link>Resources\Img\LeftMainContent\MainMenuControl_16x.png</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\fabric-icons.ttf">
+      <Link>Resources\fabric-icons.ttf</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\LeftMainContent\MainMenuControl_16x.png">
+      <Link>Resources\Img\LeftMainContent\MainMenuControl_16x.png</Link>
+    </Resource>
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="..\..\Shared\HandyControlDemo_Shared\Properties\Langs\Lang.en.resx">

src/Net_40/HandyControlDemo_Net_40/HandyControlDemo_Net_40.csproj

@@ -381,13 +381,35 @@
       <LastGenOutput>Lang.Designer.cs</LastGenOutput>
     </EmbeddedResource>
   </ItemGroup>
-  <ItemGroup />
+  <ItemGroup>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\fabric-icons.ttf">
+      <Link>Resources\fabric-icons.ttf</Link>
+    </Resource>
+  </ItemGroup>
   <ItemGroup>
     <Content Include="..\..\Shared\HandyControlDemo_Shared\Data\MessageToken.tt">
       <Link>Data\MessageToken.tt</Link>
       <Generator>TextTemplatingFileGenerator</Generator>
       <LastGenOutput>MessageToken.cs</LastGenOutput>
     </Content>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\LeftMainContent\MainMenuControl_16x.png">
+      <Link>Resources\Img\LeftMainContent\MainMenuControl_16x.png</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\DevOps\DevOps-Boards.png">
+      <Link>Resources\Img\DevOps\DevOps-Boards.png</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\DevOps\DevOps-Overview.png">
+      <Link>Resources\Img\DevOps\DevOps-Overview.png</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\DevOps\DevOps-Pipelines.png">
+      <Link>Resources\Img\DevOps\DevOps-Pipelines.png</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\DevOps\DevOps-Repos.png">
+      <Link>Resources\Img\DevOps\DevOps-Repos.png</Link>
+    </Resource>
+    <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\DevOps\DevOps-TestPlans.png">
+      <Link>Resources\Img\DevOps\DevOps-TestPlans.png</Link>
+    </Resource>
     <Resource Include="..\..\Shared\HandyControlDemo_Shared\Resources\Img\LeftMainContent\RepeatButton_16x.png">
       <Link>Resources\Img\LeftMainContent\RepeatButton_16x.png</Link>
     </Resource>

src/Shared/HandyControlDemo_Shared/HandyControlDemo_Shared.projitems

@@ -283,6 +283,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)ViewModel\Controls\NotifyIconDemoViewModel.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ViewModel\Controls\PaginationDemoViewModel.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ViewModel\Controls\SearchBarDemoViewModel.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)ViewModel\Controls\SideMenuDemoViewModel.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ViewModel\Controls\StepBarDemoViewModel.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ViewModel\Controls\WindowDemoViewModel.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ViewModel\DemoViewModelBase!1.cs" />

src/Shared/HandyControlDemo_Shared/UserControl/Controls/SideMenuDemoCtl.xaml

@@ -2,11 +2,18 @@
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:controls="clr-namespace:HandyControl.Controls;assembly=HandyControl"
-             xmlns:interactivity="clr-namespace:HandyControl.Interactivity;assembly=HandyControl"
+             xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
+             xmlns:command="http://www.galasoft.ch/mvvmlight"
+             DataContext="{Binding SideMenuDemo,Source={StaticResource Locator}}"
              Background="{DynamicResource RegionBrush}">
 
-    <Grid>
+    <controls:TransitioningContentControl>
-        <controls:SideMenu ExpandMode="ShowOne" BorderThickness="1" Width="200" Margin="32">
+        <controls:SideMenu BorderThickness="1" Width="200" Margin="32">
+            <i:Interaction.Triggers>
+                <i:EventTrigger EventName="SelectionChanged">
+                    <command:EventToCommand Command="{Binding SwitchItemCmd}" PassEventArgsToCommand="True" />
+                </i:EventTrigger>
+            </i:Interaction.Triggers>
             <controls:SideMenuItem Header="Overview">
                 <controls:SideMenuItem.Icon>
                     <Image Source="/HandyControlDemo;component/Resources/Img/DevOps/DevOps-Overview.png" Width="24" Height="24"/>
@@ -143,6 +150,6 @@
                 </controls:SideMenuItem>
             </controls:SideMenuItem>
         </controls:SideMenu>
-    </Grid>
+    </controls:TransitioningContentControl>
 
 </UserControl>

src/Shared/HandyControlDemo_Shared/UserControl/Main/LeftMainContent.xaml

@@ -203,7 +203,7 @@
                             <Image Source="../../Resources/Img/LeftMainContent/DotLarge_16x.png"/>
                         </controls:EdgeElement.LeftContent>
                     </ListBoxItem>
-                    <ListBoxItem Style="{StaticResource ListBoxItemNew}" Tag="{x:Static data:MessageToken.GotoTopDemoCtl}" Content="{x:Static langs:Lang.GotoTop}">
+                    <ListBoxItem Tag="{x:Static data:MessageToken.GotoTopDemoCtl}" Content="{x:Static langs:Lang.GotoTop}">
                         <controls:EdgeElement.LeftContent>
                             <Image Source="../../Resources/Img/LeftMainContent/GoToTop_16x.png"/>
                         </controls:EdgeElement.LeftContent>

src/Shared/HandyControlDemo_Shared/ViewModel/Controls/SideMenuDemoViewModel.cs

@@ -0,0 +1,20 @@
+using System;
+using GalaSoft.MvvmLight;
+using HandyControl.Controls;
+using HandyControl.Data;
+#if netle40
+using GalaSoft.MvvmLight.Command;
+#else
+using GalaSoft.MvvmLight.CommandWpf;
+# endif
+
+namespace HandyControlDemo.ViewModel
+{
+    public class SideMenuDemoViewModel : ViewModelBase
+    {
+        public RelayCommand<FunctionEventArgs<object>> SwitchItemCmd => new Lazy<RelayCommand<FunctionEventArgs<object>>>(() =>
+            new RelayCommand<FunctionEventArgs<object>>(SwitchItem)).Value;
+
+        private void SwitchItem(FunctionEventArgs<object> info) => Growl.Info((info.Info as SideMenuItem)?.Header.ToString());
+    }
+}

src/Shared/HandyControlDemo_Shared/ViewModel/ViewModelLocator.cs

@@ -33,6 +33,7 @@ namespace HandyControlDemo.ViewModel
             SimpleIoc.Default.Register<NotifyIconDemoViewModel>();
             SimpleIoc.Default.Register<InteractiveDialogViewModel>();
             SimpleIoc.Default.Register<BadgeDemoViewModel>();
+            SimpleIoc.Default.Register<SideMenuDemoViewModel>();
         }
 
         public static ViewModelLocator Instance => new Lazy<ViewModelLocator>(() =>
@@ -71,6 +72,9 @@ namespace HandyControlDemo.ViewModel
         public InteractiveDialogViewModel InteractiveDialog => ServiceLocator.Current.GetInstance<InteractiveDialogViewModel>();
 
         public BadgeDemoViewModel BadgeDemo => ServiceLocator.Current.GetInstance<BadgeDemoViewModel>();
+
+        public SideMenuDemoViewModel SideMenuDemo => ServiceLocator.Current.GetInstance<SideMenuDemoViewModel>();
+
         #endregion
     }
 }

src/Shared/HandyControl_Shared/Controls/SideMenu/SideMenu.cs

@@ -1,6 +1,7 @@
-using System.Windows;
+using System;
+using System.Linq;
+using System.Windows;
 using HandyControl.Data;
-using HandyControl.Data.Enum;
 
 namespace HandyControl.Controls
 {
@@ -15,6 +16,22 @@ namespace HandyControl.Controls
         public SideMenu()
         {
             AddHandler(SideMenuItem.SelectedEvent, new RoutedEventHandler(SideMenuItemSelected));
+
+            Loaded += (s, e) => Init();
+        }
+
+        protected override void Refresh()
+        {
+            base.Refresh();
+
+            Init();
+        }
+
+        private void Init()
+        {
+            if (ItemsHost == null) return;
+
+            OnExpandModeChanged(ExpandMode);
         }
 
         private void SideMenuItemSelected(object sender, RoutedEventArgs e)
@@ -23,6 +40,8 @@ namespace HandyControl.Controls
             {
                 if (item.Role == SideMenuItemRole.Item)
                 {
+                    if (Equals(item, _selectedItem)) return;
+
                     if (_selectedItem != null)
                     {
                         _selectedItem.IsSelected = false;
@@ -30,6 +49,10 @@ namespace HandyControl.Controls
 
                     _selectedItem = item;
                     _selectedItem.IsSelected = true;
+                    RaiseEvent(new FunctionEventArgs<object>(SelectionChangedEvent, this)
+                    {
+                        Info = e.OriginalSource
+                    });
                     _isItemSelected = true;
                 }
                 else
@@ -38,20 +61,36 @@ namespace HandyControl.Controls
                     {
                         if (_selectedHeader != null)
                         {
+                            if (ExpandMode == ExpandMode.Freedom && item.ItemsHost.IsVisible && !_isItemSelected)
+                            {
+                                item.IsSelected = false;
+                                SwitchPanelArea(item);
+                                return;
+                            }
+
                             _selectedHeader.IsSelected = false;
-                            SwitchPanelArea(_selectedHeader);
+                            if (ExpandMode != ExpandMode.Freedom)
+                            {
+                                SwitchPanelArea(_selectedHeader);
+                            }
                         }
 
                         _selectedHeader = item;
                         _selectedHeader.IsSelected = true;
                         SwitchPanelArea(_selectedHeader);
                     }
+                    else if (ExpandMode == ExpandMode.Freedom && !_isItemSelected)
+                    {
+                        _selectedHeader.IsSelected = false;
+                        SwitchPanelArea(_selectedHeader);
+                        _selectedHeader = null;
+                    }
 
                     if (_isItemSelected)
                     {
                         _isItemSelected = false;
                     }
-                    else
+                    else if(_selectedHeader != null)
                     {
                         _selectedHeader.SelectDefaultItem();
                         _isItemSelected = false;
@@ -67,6 +106,7 @@ namespace HandyControl.Controls
                 case ExpandMode.ShowAll:
                     return;
                 case ExpandMode.ShowOne:
+                case ExpandMode.Freedom:
                 case ExpandMode.Accordion:
                     oldItem.SwitchPanelArea(oldItem.IsSelected);
                     break;
@@ -78,12 +118,72 @@ namespace HandyControl.Controls
         protected override bool IsItemItsOwnContainerOverride(object item) => item is SideMenuItem;
 
         public static readonly DependencyProperty ExpandModeProperty = DependencyProperty.Register(
-            "ExpandMode", typeof(ExpandMode), typeof(SideMenu), new PropertyMetadata(default(ExpandMode)));
+            "ExpandMode", typeof(ExpandMode), typeof(SideMenu), new PropertyMetadata(default(ExpandMode), OnExpandModeChanged));
+
+        private static void OnExpandModeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        {
+            var ctl = (SideMenu) d;
+            var v = (ExpandMode) e.NewValue;
+
+            if (ctl.ItemsHost == null)
+            {
+                return;
+            }
+
+            ctl.OnExpandModeChanged(v);
+        }
+
+        private void OnExpandModeChanged(ExpandMode mode)
+        {
+            if (mode == ExpandMode.ShowAll)
+            {
+                ShowAll();
+            }
+            else if (mode == ExpandMode.ShowOne)
+            {
+                var sideMenuItem = ItemsHost.Children.OfType<SideMenuItem>().FirstOrDefault(item => item.IsSelected);
+                ShowSelectedOne(sideMenuItem);
+            }
+        }
 
         public ExpandMode ExpandMode
         {
             get => (ExpandMode) GetValue(ExpandModeProperty);
             set => SetValue(ExpandModeProperty, value);
         }
+
+        public static readonly DependencyProperty PanelAreaLengthProperty = DependencyProperty.Register(
+            "PanelAreaLength", typeof(double), typeof(SideMenu), new PropertyMetadata(double.NaN));
+
+        public double PanelAreaLength
+        {
+            get => (double) GetValue(PanelAreaLengthProperty);
+            set => SetValue(PanelAreaLengthProperty, value);
+        }
+
+        private void ShowAll()
+        {
+            foreach (var sideMenuItem in ItemsHost.Children.OfType<SideMenuItem>())
+            {
+                sideMenuItem.SwitchPanelArea(true);
+            }
+        }
+
+        private void ShowSelectedOne(SideMenuItem item)
+        {
+            foreach (var sideMenuItem in ItemsHost.Children.OfType<SideMenuItem>())
+            {
+                sideMenuItem.SwitchPanelArea(Equals(sideMenuItem, item));
+            }
+        }
+
+        public static readonly RoutedEvent SelectionChangedEvent = EventManager.RegisterRoutedEvent(
+            "SelectionChanged", RoutingStrategy.Bubble, typeof(EventHandler<FunctionEventArgs<object>>), typeof(SideMenu));
+
+        public event EventHandler<FunctionEventArgs<object>> SelectionChanged
+        {
+            add => AddHandler(SelectionChangedEvent, value);
+            remove => RemoveHandler(SelectionChangedEvent, value);
+        }
     }
 }

src/Shared/HandyControl_Shared/Controls/SideMenu/SideMenuItem.cs

@@ -1,5 +1,6 @@
 using System.Linq;
 using System.Windows;
+using System.Windows.Data;
 using System.Windows.Input;
 using HandyControl.Data;
 using HandyControl.Tools.Extension;
@@ -19,6 +20,54 @@ namespace HandyControl.Controls
             set => SetValue(IconProperty, value);
         }
 
+        public SideMenuItem()
+        {
+            SetBinding(ExpandModeProperty, new Binding(SideMenu.ExpandModeProperty.Name)
+            {
+                RelativeSource = new RelativeSource(RelativeSourceMode.FindAncestor, typeof(SideMenu), 1)
+            });
+        }
+
+        internal static readonly DependencyProperty ExpandModeProperty =
+            SideMenu.ExpandModeProperty.AddOwner(typeof(SideMenuItem), new PropertyMetadata(default(ExpandMode)));
+
+        internal ExpandMode ExpandMode
+        {
+            get => (ExpandMode) GetValue(ExpandModeProperty);
+            set => SetValue(ExpandModeProperty, value);
+        }
+
+        protected override void Refresh()
+        {
+            if (ItemsHost == null) return;
+
+            ItemsHost.Children.Clear();
+            foreach (var item in Items)
+            {
+                DependencyObject container;
+                if (IsItemItsOwnContainerOverride(item))
+                {
+                    container = item as DependencyObject;
+                }
+                else
+                {
+                    container = GetContainerForItemOverride();
+                    PrepareContainerForItemOverride(container, item);
+                }
+
+                if (container is FrameworkElement element)
+                {
+                    element.Style = ItemContainerStyle;
+                    ItemsHost.Children.Add(element);
+                }
+            }
+
+            if (IsLoaded)
+            {
+                SwitchPanelArea(ExpandMode == ExpandMode.ShowAll || IsSelected);
+            }
+        }
+
         protected virtual void OnSelected(RoutedEventArgs e) => RaiseEvent(e);
 
         public static readonly RoutedEvent SelectedEvent =
@@ -91,11 +140,12 @@ namespace HandyControl.Controls
             }
         }
 
-        internal void SwitchPanelArea(bool close)
+        internal void SwitchPanelArea(bool isShow)
         {
+            if (ItemsHost == null) return;
             if (Role == SideMenuItemRole.Header)
             {
-                ItemsHost.Show(close);
+                ItemsHost.Show(isShow);
             }
         }
     }

src/Shared/HandyControl_Shared/Data/Enum/ExpandMode.cs

@@ -1,17 +1,17 @@
-namespace HandyControl.Data.Enum
+namespace HandyControl.Data
 {
     public enum ExpandMode
     {
-        /// <summary>
-        ///     显示所有项，且不可折叠
-        /// </summary>
-        ShowAll,
-
         /// <summary>
         ///     最多只能显示一项，且不可折叠
         /// </summary>
         ShowOne,
 
+        /// <summary>
+        ///     显示所有项，且不可折叠
+        /// </summary>
+        ShowAll,
+
         /// <summary>
         ///     类似ShowOne，但是控件的尺寸不随项的数量而改变
         /// </summary>

src/Shared/HandyControl_Shared/Themes/Styles/Base/SideMenuBaseStyle.xaml

@@ -44,6 +44,44 @@
         </Setter>
     </Style>
 
+    <Style x:Key="SideMenuItemAccordionBaseStyle" BasedOn="{StaticResource SideMenuItemBaseStyle}" TargetType="controls:SideMenuItem">
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="controls:SideMenuItem">
+                    <Border Name="BorderRoot" Background="{TemplateBinding Background}">
+                        <controls:SimplePanel>
+                            <Rectangle Width="4" Fill="{TemplateBinding BorderBrush}" HorizontalAlignment="Left"/>
+                            <ContentControl Margin="4,0,0,0">
+                                <DockPanel Margin="{TemplateBinding Padding}">
+                                    <ContentControl Width="40" Name="PresenterIcon">
+                                        <ContentPresenter ContentSource="Icon" HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                                    </ContentControl>
+                                    <ContentPresenter Name="PresenterHeader"  ContentSource="Header" Margin="6,0,0,0" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"/>
+                                </DockPanel>
+                            </ContentControl>
+                        </controls:SimplePanel>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="Icon" Value="{x:Null}">
+                            <Setter TargetName="PresenterIcon" Property="Visibility" Value="Collapsed"/>
+                        </Trigger>
+                        <DataTrigger Binding="{Binding IsSelected,RelativeSource={RelativeSource AncestorType=controls:SideMenuItem}}" Value="True">
+                            <Setter Property="BorderBrush" Value="Transparent"/>
+                        </DataTrigger>
+                        <Trigger Property="IsSelected" Value="True">
+                            <Setter Property="BorderBrush" Value="{DynamicResource PrimaryBrush}"/>
+                            <Setter Property="Background" Value="{DynamicResource SecondaryRegionBrush}"/>
+                            <Setter Property="TextElement.FontWeight" Value="Bold" TargetName="PresenterHeader"/>
+                        </Trigger>
+                        <Trigger Property="IsMouseOver" Value="true">
+                            <Setter Property="Background" Value="{DynamicResource SecondaryRegionBrush}"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
     <Style x:Key="SideMenuItemHeaderBaseStyle" TargetType="controls:SideMenuItem">
         <Setter Property="VerticalContentAlignment" Value="Center"/>
         <Setter Property="Background" Value="{DynamicResource RegionBrush}"/>
@@ -66,7 +104,50 @@
                                     <ContentPresenter Name="PresenterHeader" ContentSource="Header" Margin="6,0,0,0" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"/>
                                 </DockPanel>
                             </ContentControl>
-                            <StackPanel Grid.Row="1" x:Name="PART_Panel"/>
+                            <StackPanel Grid.Row="1" x:Name="PART_Panel" Visibility="Collapsed" Height="{Binding PanelAreaLength,RelativeSource={RelativeSource AncestorType=controls:SideMenu}}"/>
+                        </Grid>
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="Icon" Value="{x:Null}">
+                            <Setter TargetName="PresenterIcon" Property="Visibility" Value="Collapsed"/>
+                        </Trigger>
+                        <Trigger Property="IsSelected" Value="True">
+                            <Setter TargetName="BorderBack" Property="BorderThickness" Value="4,0,0,0"/>
+                            <Setter TargetName="BorderBack" Property="BorderBrush" Value="{DynamicResource BorderBrush}"/>
+                            <Setter Property="TextElement.FontWeight" Value="Bold" TargetName="PresenterHeader"/>
+                        </Trigger>
+                        <Trigger SourceName="PanelHeader" Property="IsMouseOver" Value="true">
+                            <Setter TargetName="BorderBack" Property="Background" Value="{DynamicResource SecondaryRegionBrush}"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style x:Key="SideMenuItemHeaderAccordionBaseStyle" BasedOn="{StaticResource SideMenuItemHeaderBaseStyle}" TargetType="controls:SideMenuItem">
+        <Setter Property="ItemContainerStyle" Value="{StaticResource SideMenuItemAccordionBaseStyle}"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="controls:SideMenuItem">
+                    <Border Name="BorderRoot" Background="{TemplateBinding Background}">
+                        <Grid>
+                            <Grid.RowDefinitions>
+                                <RowDefinition MinHeight="48"/>
+                                <RowDefinition/>
+                            </Grid.RowDefinitions>
+                            <Border Name="BorderBack" Background="{TemplateBinding Background}"/>
+                            <ContentControl Grid.Row="0" Margin="4,0,0,0">
+                                <DockPanel Margin="{TemplateBinding Padding}" Name="PanelHeader" Background="Transparent">
+                                    <ContentControl Width="40" Name="PresenterIcon">
+                                        <ContentPresenter ContentSource="Icon" HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                                    </ContentControl>
+                                    <ContentPresenter Name="PresenterHeader" ContentSource="Header" Margin="6,0,0,0" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"/>
+                                </DockPanel>
+                            </ContentControl>
+                            <ScrollViewer Visibility="{Binding Visibility,ElementName=PART_Panel}" Grid.Row="1" Height="{Binding PanelAreaLength,RelativeSource={RelativeSource AncestorType=controls:SideMenu}}">
+                                <StackPanel x:Name="PART_Panel" Visibility="Collapsed"/>
+                            </ScrollViewer>
                         </Grid>
                     </Border>
                     <ControlTemplate.Triggers>

src/Shared/HandyControl_Shared/Themes/Styles/SideMenu.xaml

@@ -1,12 +1,26 @@
 <ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
+                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                     xmlns:controls="clr-namespace:HandyControl.Controls">
 
     <ResourceDictionary.MergedDictionaries>
         <ResourceDictionary Source="Base/SideMenuBaseStyle.xaml"/>
     </ResourceDictionary.MergedDictionaries>
 
-    <Style BasedOn="{StaticResource SideMenuBaseStyle}" TargetType="controls:SideMenu">
+    <Style BasedOn="{StaticResource SideMenuBaseStyle}" TargetType="controls:SideMenu"/>
 
+    <Style x:Key="SideMenuAccordion" BasedOn="{StaticResource SideMenuBaseStyle}" TargetType="controls:SideMenu">
+        <Setter Property="ExpandMode" Value="Accordion"/>
+        <Setter Property="PanelAreaLength" Value="200"/>
+        <Setter Property="ItemContainerStyle" Value="{StaticResource SideMenuItemHeaderAccordionBaseStyle}"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="controls:SideMenu">
+                    <Border Name="BorderRoot" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}">
+                        <StackPanel x:Name="PART_Panel"/>
+                    </Border>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
     </Style>
 
 </ResourceDictionary>

src/Shared/HandyControl_Shared/Tools/Helper/ConfigHelper.cs

@@ -1,7 +1,9 @@
 using System;
 using System.ComponentModel;
 using System.Globalization;
+#if !netle40
 using System.Runtime.CompilerServices;
+#endif
 using System.Windows;
 using System.Windows.Markup;
 using HandyControl.Controls;
@@ -28,7 +30,7 @@ namespace HandyControl.Tools
                 if (!_lang.IetfLanguageTag.Equals(value.IetfLanguageTag))
                 {
                     _lang = value;
-                    OnPropertyChanged();
+                    OnPropertyChanged(nameof(Lang));
                 }
             }
         }
@@ -52,9 +54,16 @@ namespace HandyControl.Tools
 
         public event PropertyChangedEventHandler PropertyChanged;
 
-        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
+#if netle40
+        protected virtual void OnPropertyChanged(string propertyName)
         {
             PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
         }
+#else
+        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }  
+#endif
     }
 }