How to change the width of combobox scrollbar?

To change the width of Combobox scollbar in WPF, you need to change the style of Combobox and the control template of the scrollviewier. Don't be afraid of the very vast code. It is automatically generated when we style it using Expression Blend. We just need to modify the required parameters. Below is the sample xaml code which you can copy and use it.

Combobox scrollbar

<Window

       xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

       xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

       xmlns:Microsoft_Windows_Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero"

       x:Class="ComboboxScollbar.MainWindow"

       x:Name="Window"

       Title="MainWindow"

       Width="640" Height="480">

      

       <Window.Resources>                                                 

              <Style x:Key="ComboBoxFocusVisual">

                     <Setter Property="Control.Template">

                           <Setter.Value>

                                  <ControlTemplate>

                                         <Rectangle Margin="4,4,21,4" SnapsToDevicePixels="true" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" StrokeThickness="1" StrokeDashArray="1 2"/>

                                  </ControlTemplate>

                           </Setter.Value>

                     </Setter>

              </Style>

              <LinearGradientBrush x:Key="ButtonNormalBackground" EndPoint="0,1" StartPoint="0,0">

                     <GradientStop Color="#F3F3F3" Offset="0"/>

                     <GradientStop Color="#EBEBEB" Offset="0.5"/>

                     <GradientStop Color="#DDDDDD" Offset="0.5"/>

                     <GradientStop Color="#CDCDCD" Offset="1"/>

              </LinearGradientBrush>

              <SolidColorBrush x:Key="ButtonNormalBorder" Color="#FF707070"/>

              <Geometry x:Key="DownArrowGeometry">M 0 0 L 3.5 4 L 7 0 Z</Geometry>

              <Style x:Key="ComboBoxReadonlyToggleButton" TargetType="{x:Type ToggleButton}">

                     <Setter Property="OverridesDefaultStyle" Value="true"/>

                     <Setter Property="IsTabStop" Value="false"/>

                     <Setter Property="Focusable" Value="false"/>

                     <Setter Property="ClickMode" Value="Press"/>

                     <Setter Property="Template">

                           <Setter.Value>

                                  <ControlTemplate TargetType="{x:Type ToggleButton}">

                                         <Microsoft_Windows_Themes:ButtonChrome x:Name="Chrome" BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" RenderMouseOver="{TemplateBinding IsMouseOver}" RenderPressed="{TemplateBinding IsPressed}" SnapsToDevicePixels="true">

                                                <Grid HorizontalAlignment="Right" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}">

                                                       <Path x:Name="Arrow" Data="{StaticResource DownArrowGeometry}" Fill="Black" HorizontalAlignment="Center" Margin="3,1,0,0" VerticalAlignment="Center"/>

                                                </Grid>

                                         </Microsoft_Windows_Themes:ButtonChrome>

                                         <ControlTemplate.Triggers>

                                                <Trigger Property="IsChecked" Value="true">

                                                       <Setter Property="RenderPressed" TargetName="Chrome" Value="true"/>

                                                </Trigger>

                                                <Trigger Property="IsEnabled" Value="false">

                                                       <Setter Property="Fill" TargetName="Arrow" Value="#AFAFAF"/>

                                                </Trigger>

                                         </ControlTemplate.Triggers>

                                  </ControlTemplate>

                           </Setter.Value>

                     </Setter>

              </Style>

              <LinearGradientBrush x:Key="TextBoxBorder" EndPoint="0,20" MappingMode="Absolute" StartPoint="0,0">

                     <GradientStop Color="#ABADB3" Offset="0.05"/>

                     <GradientStop Color="#E2E3EA" Offset="0.07"/>

                     <GradientStop Color="#E3E9EF" Offset="1"/>

              </LinearGradientBrush>

              <Style x:Key="ComboBoxEditableTextBox" TargetType="{x:Type TextBox}">

                     <Setter Property="OverridesDefaultStyle" Value="true"/>

                     <Setter Property="AllowDrop" Value="true"/>

                     <Setter Property="MinWidth" Value="0"/>

                     <Setter Property="MinHeight" Value="0"/>

                     <Setter Property="FocusVisualStyle" Value="{x:Null}"/>

                     <Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst"/>

                     <Setter Property="Stylus.IsFlicksEnabled" Value="False"/>

                     <Setter Property="Template">

                           <Setter.Value>

                                  <ControlTemplate TargetType="{x:Type TextBox}">

                                         <ScrollViewer x:Name="PART_ContentHost" Background="Transparent" Focusable="false" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden"/>

                                  </ControlTemplate>

                           </Setter.Value>

                     </Setter>

              </Style>

              <Style x:Key="ComboBoxToggleButton" TargetType="{x:Type ToggleButton}">

                     <Setter Property="OverridesDefaultStyle" Value="true"/>

                     <Setter Property="IsTabStop" Value="false"/>

                     <Setter Property="Focusable" Value="false"/>

                     <Setter Property="ClickMode" Value="Press"/>

                     <Setter Property="Template">

                           <Setter.Value>

                                  <ControlTemplate TargetType="{x:Type ToggleButton}">

                                         <Microsoft_Windows_Themes:ButtonChrome x:Name="Chrome" BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" RenderMouseOver="{TemplateBinding IsMouseOver}" RenderPressed="{TemplateBinding IsPressed}" RoundCorners="false" SnapsToDevicePixels="true" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}">

                                                <Path x:Name="Arrow" Data="{StaticResource DownArrowGeometry}" Fill="Black" HorizontalAlignment="Center" Margin="0,1,0,0" VerticalAlignment="Center"/>

                                         </Microsoft_Windows_Themes:ButtonChrome>

                                         <ControlTemplate.Triggers>

                                                <Trigger Property="IsChecked" Value="true">

                                                       <Setter Property="RenderPressed" TargetName="Chrome" Value="true"/>

                                                </Trigger>

                                                <Trigger Property="IsEnabled" Value="false">

                                                       <Setter Property="Fill" TargetName="Arrow" Value="#AFAFAF"/>

                                                </Trigger>

                                         </ControlTemplate.Triggers>

                                  </ControlTemplate>

                           </Setter.Value>

                     </Setter>

              </Style>

              <ControlTemplate x:Key="ComboBoxEditableTemplate" TargetType="{x:Type ComboBox}">

                     <Grid x:Name="Placement" SnapsToDevicePixels="true">

                           <Grid.ColumnDefinitions>

                                  <ColumnDefinition Width="*"/>

                                  <ColumnDefinition Width="Auto"/>

                           </Grid.ColumnDefinitions>

                           <Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">

                                  <Microsoft_Windows_Themes:SystemDropShadowChrome x:Name="Shdw" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=Placement}">

                                         <Border x:Name="DropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">

                                                <ScrollViewer x:Name="DropDownScrollViewer">

                                                       <Grid RenderOptions.ClearTypeHint="Enabled">

                                                              <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">

                                                                     <Rectangle x:Name="OpaqueRect" Fill="{Binding Background, ElementName=DropDownBorder}" Height="{Binding ActualHeight, ElementName=DropDownBorder}" Width="{Binding ActualWidth, ElementName=DropDownBorder}"/>

                                                              </Canvas>

                                                              <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>

                                                       </Grid>

                                                </ScrollViewer>

                                         </Border>

                                  </Microsoft_Windows_Themes:SystemDropShadowChrome>

                           </Popup>

                           <Microsoft_Windows_Themes:ListBoxChrome x:Name="Border" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" RenderMouseOver="{TemplateBinding IsMouseOver}" RenderFocused="{TemplateBinding IsKeyboardFocusWithin}"/>

                           <TextBox x:Name="PART_EditableTextBox" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" IsReadOnly="{Binding IsReadOnly, RelativeSource={RelativeSource TemplatedParent}}" Margin="{TemplateBinding Padding}" Style="{StaticResource ComboBoxEditableTextBox}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>

                           <ToggleButton Grid.Column="1" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>

                     </Grid>

                     <ControlTemplate.Triggers>

                           <Trigger Property="IsKeyboardFocusWithin" Value="true">

                                  <Setter Property="Foreground" Value="Black"/>

                           </Trigger>

                           <Trigger Property="IsDropDownOpen" Value="true">

                                  <Setter Property="RenderFocused" TargetName="Border" Value="true"/>

                           </Trigger>

                           <Trigger Property="HasItems" Value="false">

                                  <Setter Property="Height" TargetName="DropDownBorder" Value="95"/>

                           </Trigger>

                           <Trigger Property="IsEnabled" Value="false">

                                  <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>

                                  <Setter Property="Background" Value="#FFF4F4F4"/>

                           </Trigger>

                           <Trigger Property="IsGrouping" Value="true">

                                  <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>

                           </Trigger>

                           <Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">

                                  <Setter Property="Margin" TargetName="Shdw" Value="0,0,5,5"/>

                                  <Setter Property="Color" TargetName="Shdw" Value="#71000000"/>

                           </Trigger>

                           <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">

                                  <Setter Property="Canvas.Top" TargetName="OpaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>

                                  <Setter Property="Canvas.Left" TargetName="OpaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>

                           </Trigger>

                     </ControlTemplate.Triggers>

              </ControlTemplate>

              <Style x:Key="ComboBoxStyle1" TargetType="{x:Type ComboBox}">

                     <Setter Property="FocusVisualStyle" Value="{StaticResource ComboBoxFocusVisual}"/>

                     <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/>

                     <Setter Property="Background" Value="{StaticResource ButtonNormalBackground}"/>

                     <Setter Property="BorderBrush" Value="{StaticResource ButtonNormalBorder}"/>

                     <Setter Property="BorderThickness" Value="1"/>

                     <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>

                     <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>

                     <Setter Property="Padding" Value="4,3"/>

                     <Setter Property="ScrollViewer.CanContentScroll" Value="true"/>

                     <Setter Property="ScrollViewer.PanningMode" Value="Both"/>

                     <Setter Property="Stylus.IsFlicksEnabled" Value="False"/>

                     <Setter Property="Template">

                           <Setter.Value>

                                  <ControlTemplate TargetType="{x:Type ComboBox}">

                                         <Grid x:Name="MainGrid" SnapsToDevicePixels="true">

                                                <Grid.ColumnDefinitions>

                                                       <ColumnDefinition Width="*"/>

                                                       <ColumnDefinition Width="40"/>

                                                </Grid.ColumnDefinitions>

                                                <Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">

                                                       <Microsoft_Windows_Themes:SystemDropShadowChrome x:Name="Shdw" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=MainGrid}">

                                                              <Border x:Name="DropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">

                                                                     <ScrollViewer x:Name="DropDownScrollViewer" Template="{DynamicResource ScrollViewerControlTemplate1}">

                                                                           <Grid RenderOptions.ClearTypeHint="Enabled">

                                                                                  <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">

                                                                                         <Rectangle x:Name="OpaqueRect" Fill="{Binding Background, ElementName=DropDownBorder}" Height="{Binding ActualHeight, ElementName=DropDownBorder}" Width="{Binding ActualWidth, ElementName=DropDownBorder}"/>

                                                                                  </Canvas>

                                                                                  <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>

                                                                           </Grid>

                                                                     </ScrollViewer>

                                                              </Border>

                                                       </Microsoft_Windows_Themes:SystemDropShadowChrome>

                                                </Popup>

                                                <ToggleButton BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxReadonlyToggleButton}"/>

                                                <ContentPresenter ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" Content="{TemplateBinding SelectionBoxItem}" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="false" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>

                                         </Grid>

                                         <ControlTemplate.Triggers>

                                                <Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">

                                                      <Setter Property="Margin" TargetName="Shdw" Value="0,0,5,5"/>

                                                       <Setter Property="Color" TargetName="Shdw" Value="#71000000"/>

                                                </Trigger>

                                                <Trigger Property="HasItems" Value="false">

                                                       <Setter Property="Height" TargetName="DropDownBorder" Value="95"/>

                                                </Trigger>

                                                <Trigger Property="IsEnabled" Value="false">

                                                       <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>

                                                       <Setter Property="Background" Value="#FFF4F4F4"/>

                                                </Trigger>

                                                <Trigger Property="IsGrouping" Value="true">

                                                       <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>

                                                </Trigger>

                                                <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">

                                                       <Setter Property="Canvas.Top" TargetName="OpaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>

                                                       <Setter Property="Canvas.Left" TargetName="OpaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>

                                                </Trigger>

                                         </ControlTemplate.Triggers>

                                  </ControlTemplate>

                           </Setter.Value>

                     </Setter>

                     <Style.Triggers>

                           <Trigger Property="IsEditable" Value="true">

                                  <Setter Property="BorderBrush" Value="{StaticResource TextBoxBorder}"/>

                                  <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.WindowBrushKey}}"/>

                                  <Setter Property="IsTabStop" Value="false"/>

                                  <Setter Property="Padding" Value="3"/>

                                  <Setter Property="Template" Value="{StaticResource ComboBoxEditableTemplate}"/>

                           </Trigger>

                     </Style.Triggers>

              </Style>

              <ControlTemplate x:Key="ScrollViewerControlTemplate1" TargetType="{x:Type ScrollViewer}">

                     <Grid x:Name="Grid" Background="{TemplateBinding Background}">

                           <Grid.ColumnDefinitions>

                                  <ColumnDefinition Width="*"/>

                                  <ColumnDefinition Width="40"/>

                           </Grid.ColumnDefinitions>

                           <Grid.RowDefinitions>

                                  <RowDefinition Height="*"/>

                                  <RowDefinition Height="Auto"/>

                           </Grid.RowDefinitions>

                           <Rectangle x:Name="Corner" Grid.Column="1" Fill="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" Grid.Row="1"/>

                           <ScrollContentPresenter x:Name="PART_ScrollContentPresenter" CanContentScroll="{TemplateBinding CanContentScroll}" CanHorizontallyScroll="False" CanVerticallyScroll="False" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Grid.Column="0" Margin="{TemplateBinding Padding}" Grid.Row="0"/>

                           <ScrollBar Width="40" x:Name="PART_VerticalScrollBar" AutomationProperties.AutomationId="VerticalScrollBar" Cursor="Arrow" Grid.Column="1" Maximum="{TemplateBinding ScrollableHeight}" Minimum="0" Grid.Row="0" Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}" Value="{Binding VerticalOffset, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}" ViewportSize="{TemplateBinding ViewportHeight}" Style="{DynamicResource ScrollBarStyle1}"/>

                           <ScrollBar x:Name="PART_HorizontalScrollBar" AutomationProperties.AutomationId="HorizontalScrollBar" Cursor="Arrow" Grid.Column="0" Maximum="{TemplateBinding ScrollableWidth}" Minimum="0" Orientation="Horizontal" Grid.Row="1" Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}" Value="{Binding HorizontalOffset, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}" ViewportSize="{TemplateBinding ViewportWidth}"/>

                     </Grid>

              </ControlTemplate>

              <LinearGradientBrush x:Key="VerticalScrollBarBackground" EndPoint="1,0" StartPoint="0,0">

                     <GradientStop Color="#E1E1E1" Offset="0"/>

                     <GradientStop Color="#EDEDED" Offset="0.20"/>

                     <GradientStop Color="#EDEDED" Offset="0.80"/>

                     <GradientStop Color="#E3E3E3" Offset="1"/>

              </LinearGradientBrush>

              <SolidColorBrush x:Key="ScrollBarDisabledBackground" Color="#F4F4F4"/>

              <Style x:Key="ScrollBarButton" TargetType="{x:Type RepeatButton}">

                     <Setter Property="OverridesDefaultStyle" Value="true"/>

                     <Setter Property="Focusable" Value="false"/>

                     <Setter Property="IsTabStop" Value="false"/>

                     <Setter Property="Template">

                           <Setter.Value>

                                  <ControlTemplate TargetType="{x:Type RepeatButton}">

                                         <Microsoft_Windows_Themes:ScrollChrome x:Name="Chrome" RenderMouseOver="{TemplateBinding IsMouseOver}" RenderPressed="{TemplateBinding IsPressed}" SnapsToDevicePixels="true" Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph="{TemplateBinding Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph}"/>

                                  </ControlTemplate>

                           </Setter.Value>

                     </Setter>

              </Style>

              <Style x:Key="VerticalScrollBarPageButton" TargetType="{x:Type RepeatButton}">

                     <Setter Property="OverridesDefaultStyle" Value="true"/>

                     <Setter Property="Background" Value="Transparent"/>

                     <Setter Property="Focusable" Value="false"/>

                     <Setter Property="IsTabStop" Value="false"/>

                     <Setter Property="Template">

                           <Setter.Value>

                                  <ControlTemplate TargetType="{x:Type RepeatButton}">

                                         <Rectangle Fill="{TemplateBinding Background}" Height="{TemplateBinding Height}" Width="{TemplateBinding Width}"/>

                                  </ControlTemplate>

                            </Setter.Value>

                     </Setter>

              </Style>

              <Style x:Key="ScrollBarThumb" TargetType="{x:Type Thumb}">

                     <Setter Property="OverridesDefaultStyle" Value="true"/>

                     <Setter Property="IsTabStop" Value="false"/>

                     <Setter Property="Template">

                           <Setter.Value>

                                  <ControlTemplate TargetType="{x:Type Thumb}">

                                         <Microsoft_Windows_Themes:ScrollChrome x:Name="Chrome" RenderMouseOver="{TemplateBinding IsMouseOver}" RenderPressed="{TemplateBinding IsDragging}" SnapsToDevicePixels="true" Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph="{TemplateBinding Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph}"/>

                                  </ControlTemplate>

                           </Setter.Value>

                     </Setter>

              </Style>

              <LinearGradientBrush x:Key="HorizontalScrollBarBackground" EndPoint="0,1" StartPoint="0,0">

                     <GradientStop Color="#E1E1E1" Offset="0"/>

                     <GradientStop Color="#EDEDED" Offset="0.20"/>

                     <GradientStop Color="#EDEDED" Offset="0.80"/>

                     <GradientStop Color="#E3E3E3" Offset="1"/>

              </LinearGradientBrush>

              <Style x:Key="HorizontalScrollBarPageButton" TargetType="{x:Type RepeatButton}">

                     <Setter Property="OverridesDefaultStyle" Value="true"/>

                     <Setter Property="Background" Value="Transparent"/>

                     <Setter Property="Focusable" Value="false"/>

                     <Setter Property="IsTabStop" Value="false"/>

                     <Setter Property="Template">

                           <Setter.Value>

                                  <ControlTemplate TargetType="{x:Type RepeatButton}">

                                         <Rectangle Fill="{TemplateBinding Background}" Height="{TemplateBinding Height}" Width="{TemplateBinding Width}"/>

                                  </ControlTemplate>

                           </Setter.Value>

                     </Setter>

              </Style>

             

       <Style x:Key="ScrollBarStyle1" TargetType="{x:Type ScrollBar}">

              <Setter Property="Stylus.IsPressAndHoldEnabled" Value="false"/>

              <Setter Property="Stylus.IsFlicksEnabled" Value="false"/>

              <Setter Property="Background" Value="{StaticResource VerticalScrollBarBackground}"/>

              <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>

              <Setter Property="Width" Value="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}"/>

              <Setter Property="MinWidth" Value="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}"/>

              <Setter Property="Template">

                     <Setter.Value>

                           <ControlTemplate TargetType="{x:Type ScrollBar}">

                                  <Grid Background="Transparent" SnapsToDevicePixels="true">

                                         <Grid.RowDefinitions>

                                                <RowDefinition Height="50"/>

                                                <RowDefinition Height="*"/>

                                                <RowDefinition Height="50"/>

                                         </Grid.RowDefinitions>

                                         <RepeatButton Command="{x:Static ScrollBar.LineUpCommand}" Style="{StaticResource ScrollBarButton}" Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph="UpArrow"/>

                                         <Track x:Name="PART_Track" IsDirectionReversed="true" Grid.Row="1">

                                                <Track.DecreaseRepeatButton>

                                                       <RepeatButton Command="{x:Static ScrollBar.PageUpCommand}" Style="{StaticResource VerticalScrollBarPageButton}"/>

                                                </Track.DecreaseRepeatButton>

                                                <Track.IncreaseRepeatButton>

                                                       <RepeatButton Command="{x:Static ScrollBar.PageDownCommand}" Style="{StaticResource VerticalScrollBarPageButton}"/>

                                                </Track.IncreaseRepeatButton>

                                                <Track.Thumb>

                                                       <Thumb Style="{StaticResource ScrollBarThumb}" Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph="VerticalGripper"/>

                                                </Track.Thumb>

                                         </Track>

                                         <RepeatButton Command="{x:Static ScrollBar.LineDownCommand}" Grid.Row="2" Style="{StaticResource ScrollBarButton}" Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph="DownArrow"/>

                                  </Grid>

                           </ControlTemplate>

                     </Setter.Value>

              </Setter>

              <Style.Triggers>

                     <Trigger Property="Orientation" Value="Horizontal">

                           <Setter Property="Width" Value="Auto"/>

                           <Setter Property="MinWidth" Value="0"/>

                           <Setter Property="Background" Value="{StaticResource HorizontalScrollBarBackground}"/>

                           <Setter Property="Height" Value="{DynamicResource {x:Static SystemParameters.HorizontalScrollBarHeightKey}}"/>

                           <Setter Property="MinHeight" Value="{DynamicResource {x:Static SystemParameters.HorizontalScrollBarHeightKey}}"/>

                           <Setter Property="Template">

                                  <Setter.Value>

                                         <ControlTemplate TargetType="{x:Type ScrollBar}">

                                                <Grid Background="{TemplateBinding Background}" SnapsToDevicePixels="true">

                                                       <Grid.ColumnDefinitions>

                                                              <ColumnDefinition MaxWidth="{DynamicResource {x:Static SystemParameters.HorizontalScrollBarButtonWidthKey}}"/>

                                                              <ColumnDefinition Width="0.00001*"/>

                                                              <ColumnDefinition MaxWidth="{DynamicResource {x:Static SystemParameters.HorizontalScrollBarButtonWidthKey}}"/>

                                                       </Grid.ColumnDefinitions>

                                                       <RepeatButton Command="{x:Static ScrollBar.LineLeftCommand}" Style="{StaticResource ScrollBarButton}" Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph="LeftArrow"/>

                                                       <Track x:Name="PART_Track" Grid.Column="1">

                                                              <Track.DecreaseRepeatButton>

                                                                     <RepeatButton Command="{x:Static ScrollBar.PageLeftCommand}" Style="{StaticResource HorizontalScrollBarPageButton}"/>

                                                              </Track.DecreaseRepeatButton>

                                                              <Track.IncreaseRepeatButton>

                                                                     <RepeatButton Command="{x:Static ScrollBar.PageRightCommand}" Style="{StaticResource HorizontalScrollBarPageButton}"/>

                                                              </Track.IncreaseRepeatButton>

                                                              <Track.Thumb>

                                                                     <Thumb Style="{StaticResource ScrollBarThumb}" Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph="HorizontalGripper"/>

                                                              </Track.Thumb>

                                                       </Track>

                                                       <RepeatButton Grid.Column="2" Command="{x:Static ScrollBar.LineRightCommand}" Style="{StaticResource ScrollBarButton}" Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph="RightArrow"/>

                                                </Grid>

                                         </ControlTemplate>

                                  </Setter.Value>

                           </Setter>

                     </Trigger>

              </Style.Triggers>

       </Style>

                          

       </Window.Resources>

      

       <Grid x:Name="LayoutRoot">

              <Grid.RowDefinitions>

                     <RowDefinition Height="50"/>

                     <RowDefinition/>

              </Grid.RowDefinitions>

              <ComboBox ScrollViewer.VerticalScrollBarVisibility="Visible" VerticalAlignment="Top" Style="{DynamicResource ComboBoxStyle1}" >

                     <ComboBoxItem>1</ComboBoxItem>

                     <ComboBoxItem>2</ComboBoxItem>                        

              </ComboBox>

             

       </Grid>

</Window>