RichTextBox FocusVisualStyle无法正常工作

Question

I have a RichTextBox that has some content. I want to hide the scrollbar and remove the border when the user moves the mouse over it. I have added FocusVisualStyle="{x:Null}" which I read in this link: Remove focus rectangle on a UserControl

See below:

 <RichTextBox HorizontalAlignment="Left" Height="105" Margin="48,42,0,0" VerticalAlignment="Top" Width="614" Background="Transparent" IsReadOnly="True" ScrollViewer.VerticalScrollBarVisibility="Hidden"  BorderBrush="Transparent" ScrollViewer.CanContentScroll="False"  FocusVisualStyle="{x:Null}">
      </FlowDocument>
         blah blah 
      </FlowDocument>
 </RichTextBox>

But wheneever the user moves the mouse over it I still see a white border appear and I can scroll up and down.

Why is this??

Answer 1

That's not FocusVisual you are seeing instead its MouseOver effect which is applied by default for RichTextBox.

You need to override default template to remove that effect which is applied via trigger ( in case UIElement.IsMouseOver value is true ).

Create a style and provide your own template ( In case you want it to be applied for all RichTextBoxes in your app put this in app resources or window resources wherever it fits in your code. Otherwise you can declare it inline just for your RichTextbox):

<Style TargetType="RichTextBox">
   <Setter Property="Template">
      <Setter.Value>
         <ControlTemplate TargetType="TextBoxBase">
            <Border BorderThickness="{TemplateBinding Border.BorderThickness}"
                    BorderBrush="{TemplateBinding Border.BorderBrush}"
                    Background="{TemplateBinding Panel.Background}"
                    Name="border"
                    SnapsToDevicePixels="True">
               <ScrollViewer HorizontalScrollBarVisibility="Hidden"
                             VerticalScrollBarVisibility="Hidden"
                             Name="PART_ContentHost"
                             Focusable="False" />
            </Border>
            <ControlTemplate.Triggers>
                <Trigger Property="UIElement.IsEnabled" Value="False">
                    <Setter Property="UIElement.Opacity" TargetName="border" 
                            Value="0.56"/>
                </Trigger>
            <!--<Trigger Property="UIElement.IsMouseOver" Value="True">
                    <Setter Property="Border.BorderBrush" TargetName="border">
                       <Setter.Value>
                          <SolidColorBrush>#FF7EB4EA</SolidColorBrush>
                       </Setter.Value>
                    </Setter>
                </Trigger>-->
                <Trigger Property="UIElement.IsKeyboardFocused" Value="True">
                   <Setter Property="Border.BorderBrush" TargetName="border">
                      <Setter.Value>
                         <SolidColorBrush>#FF569DE5</SolidColorBrush>
                      </Setter.Value>
                   </Setter>
                 </Trigger>
              </ControlTemplate.Triggers>
           </ControlTemplate>
        </Setter.Value>
     </Setter>
  </Style>

Notice the trigger i have commented in the above default template.