Changing scroll-bars color of a ListBox on Windows Phone 7

Question

I have a <ListBox> item with a white background, I want to change the scroll-bars color so that they can be visible when the user scrolls the items.

How can I achieve this?

Answer 1

You can change the VisualState of the Scrolling state. You want to edit the ListBox's ScrollViewer's VerticalScrollBar template. For example, this style is 100% opacity and red:

<Style x:Key="ScrollViewerStyle1" TargetType="ScrollViewer">
            <Setter Property="VerticalScrollBarVisibility" Value="Auto"/>
            <Setter Property="HorizontalScrollBarVisibility" Value="Disabled"/>
            <Setter Property="Background" Value="Transparent"/>
            <Setter Property="Padding" Value="0"/>
            <Setter Property="BorderThickness" Value="0"/>
            <Setter Property="BorderBrush" Value="Transparent"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="ScrollViewer">
                        <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}">
                            <VisualStateManager.VisualStateGroups>
                                <VisualStateGroup x:Name="ScrollStates">
                                    <VisualStateGroup.Transitions>
                                        <VisualTransition GeneratedDuration="00:00:00.5"/>
                                    </VisualStateGroup.Transitions>
                                    <VisualState x:Name="Scrolling">
                                        <Storyboard>
                                            <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="VerticalScrollBar"/>
                                            <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="HorizontalScrollBar"/>
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="NotScrolling"/>
                                </VisualStateGroup>
                            </VisualStateManager.VisualStateGroups>
                            <Grid Margin="{TemplateBinding Padding}">
                                <ScrollContentPresenter x:Name="ScrollContentPresenter" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}"/>
                                <ScrollBar x:Name="VerticalScrollBar" HorizontalAlignment="Right" Height="Auto" IsHitTestVisible="False" IsTabStop="False" Maximum="{TemplateBinding ScrollableHeight}" Minimum="0" Opacity="0" Orientation="Vertical" Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}" Value="{TemplateBinding VerticalOffset}" ViewportSize="{TemplateBinding ViewportHeight}" VerticalAlignment="Stretch" Width="5" Background="Red"/>
                                <ScrollBar x:Name="HorizontalScrollBar" HorizontalAlignment="Stretch" Height="5" IsHitTestVisible="False" IsTabStop="False" Maximum="{TemplateBinding ScrollableWidth}" Minimum="0" Opacity="0" Orientation="Horizontal" Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}" Value="{TemplateBinding HorizontalOffset}" ViewportSize="{TemplateBinding ViewportWidth}" VerticalAlignment="Bottom" Width="Auto"/>
                            </Grid>
                        </Border>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

and the ListBox's style (which uses the above VerticalScrollBar template) is like this:

<Style x:Key="ListBoxStyle1" TargetType="ListBox">
            <Setter Property="Background" Value="Transparent"/>
            <Setter Property="Foreground" Value="{StaticResource PhoneForegroundBrush}"/>
            <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled"/>
            <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
            <Setter Property="BorderThickness" Value="0"/>
            <Setter Property="BorderBrush" Value="Transparent"/>
            <Setter Property="Padding" Value="0"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="ListBox">
                        <ScrollViewer x:Name="ScrollViewer" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Foreground="{TemplateBinding Foreground}" Padding="{TemplateBinding Padding}" Style="{StaticResource ScrollViewerStyle1}" >

                            <ItemsPresenter/>
                        </ScrollViewer>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

You can use Expression Blend to craft the XAML as it's much more efficient.