c# wpf Changing color of thumb/scrollbox RichTextBox

Question

i want to change color of thumb/scrollbox from RichTextBox.

I'm using, but it doesn't changes color of thumb

<RichTextBox x:Name="richTextBox" HorizontalAlignment="Left" Height="285" VerticalAlignment="Top" Width="880" VerticalScrollBarVisibility="Visible" IsReadOnly="True" Foreground="#FFA02626" Background="{x:Null}">
            <RichTextBox.Resources>
                <Style TargetType="ScrollBar">
                    <Setter Property="Foreground" Value="Red"/>
                </Style>
            </RichTextBox.Resources>
</RichTextBox>

Answer 1

I don't find any easy way to do this. But you can define your custom ScrollBar style. Here is my example I just wrote. It's look so ugly because I'm going to bed.

<RichTextBox>            
            <RichTextBox.Resources>
            <Style x:Key="ScrollThumb" TargetType="{x:Type Thumb}">
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type Thumb}">
                            <Rectangle x:Name="Rectangle1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Fill="Transparent" SnapsToDevicePixels="True"/>
                            <ControlTemplate.Triggers>
                                <Trigger Property="Tag" Value="Horizontal">
                                    <Setter TargetName="Rectangle1" Property="Width" Value="Auto" />
                                    <Setter TargetName="Rectangle1" Property="Height" Value="7" />
                                </Trigger>
                            </ControlTemplate.Triggers>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
            <Style x:Key="{x:Type ScrollBar}" TargetType="{x:Type ScrollBar}">
                <Setter Property="Stylus.IsFlicksEnabled" Value="false" />
                <Setter Property="Foreground" Value="Red" />
                <Setter Property="Background" Value="DarkGray" />
                <Setter Property="Width" Value="10" />
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type ScrollBar}">
                            <Grid x:Name="GridRoot" Width="19" Background="{TemplateBinding Background}">
                                <Grid.RowDefinitions>
                                    <RowDefinition Height="0.00001*" />
                                </Grid.RowDefinitions>

                                <Track x:Name="PART_Track" Grid.Row="0" IsDirectionReversed="true" Focusable="false">
                                    <Track.Thumb>
                                        <Thumb x:Name="Thumb" Background="{TemplateBinding Foreground}" Style="{DynamicResource ScrollThumbs}" />
                                    </Track.Thumb>
                                    <Track.IncreaseRepeatButton>
                                        <RepeatButton x:Name="PageUp" Command="ScrollBar.PageDownCommand" Opacity="0" Focusable="false" />
                                    </Track.IncreaseRepeatButton>
                                    <Track.DecreaseRepeatButton>
                                        <RepeatButton x:Name="PageDown" Command="ScrollBar.PageUpCommand" Opacity="0" Focusable="false" />
                                    </Track.DecreaseRepeatButton>
                                </Track>
                            </Grid>

                            <ControlTemplate.Triggers>
                                <Trigger SourceName="Thumb" Property="IsMouseOver" Value="true">
                                    <Setter Value="{DynamicResource ButtonSelectBrush}" TargetName="Thumb" Property="Background" />
                                </Trigger>
                                <Trigger SourceName="Thumb" Property="IsDragging" Value="true">
                                    <Setter Value="{DynamicResource DarkBrush}" TargetName="Thumb" Property="Background" />
                                </Trigger>

                                <Trigger Property="IsEnabled" Value="false">
                                    <Setter TargetName="Thumb" Property="Visibility" Value="Collapsed" />
                                </Trigger>
                                <Trigger Property="Orientation" Value="Horizontal">
                                    <Setter TargetName="GridRoot" Property="LayoutTransform">
                                        <Setter.Value>
                                            <RotateTransform Angle="-90" />
                                        </Setter.Value>
                                    </Setter>
                                    <Setter TargetName="PART_Track" Property="LayoutTransform">
                                        <Setter.Value>
                                            <RotateTransform Angle="-90" />
                                        </Setter.Value>
                                    </Setter>
                                    <Setter Property="Width" Value="Auto" />
                                    <Setter Property="Height" Value="12" />
                                    <Setter TargetName="Thumb" Property="Tag" Value="Horizontal" />
                                    <Setter TargetName="PageDown" Property="Command" Value="ScrollBar.PageLeftCommand" />
                                    <Setter TargetName="PageUp" Property="Command" Value="ScrollBar.PageRightCommand" />
                                </Trigger>
                            </ControlTemplate.Triggers>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
        </RichTextBox.Resources>
    </RichTextBox>

You can improve it follow MS guide here : https://msdn.microsoft.com/en-us/library/ms742173(v=vs.110).aspx Or here: https://www.google.com