Disabling text selection in DocumentViewer

Simple question. How do you disable the text selection of DocumentViewer in WPF? This is the feature where an XPS document is displayed by the viewer and then text can be highlighted via mouse. The highlighted text can also be copied but I have already disabled this. I just don't know how to disable the highlighting.

Thanks!

We have solved this by overriding the ControlTemplate of the ScrollViewer embedded in the DocumentViewer control. Insert the Style below in "Window.Resources":

<Style TargetType="{x:Type ScrollViewer}"  x:Key="CustomScrollPresenter">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ScrollViewer}">
                <Grid Background="{TemplateBinding Panel.Background}">
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="*" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="*" />
                        <RowDefinition Height="Auto" />
                    </Grid.RowDefinitions>
                    <Rectangle Grid.Column="1" Grid.Row="1" Fill="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" />
                    <ScrollContentPresenter 
                        PreviewMouseLeftButtonDown="ScrollContentPresenter_PreviewMouseLeftButtonDown"
                        Grid.Column="0" 
                        Grid.Row="0" 
                        Margin="{TemplateBinding Control.Padding}" 
                        Content="{TemplateBinding ContentControl.Content}" 
                        ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}" 
                        CanContentScroll="{TemplateBinding ScrollViewer.CanContentScroll}" />
                    <ScrollBar 
                        x:Name="PART_VerticalScrollBar"
                        Grid.Column="1" 
                               Grid.Row="0" 
                               Minimum="0" 
                               Maximum="{TemplateBinding ScrollViewer.ScrollableHeight}" 
                               ViewportSize="{TemplateBinding ScrollViewer.ViewportHeight}" 
                               Value="{Binding Path=VerticalOffset, Mode=OneWay, RelativeSource={RelativeSource Mode=TemplatedParent}}" 
                               Visibility="{TemplateBinding ScrollViewer.ComputedVerticalScrollBarVisibility}" 
                               Cursor="Arrow" AutomationProperties.AutomationId="VerticalScrollBar" />
                    <ScrollBar 
                        x:Name="PART_HorizontalScrollBar"
                        Orientation="Horizontal" Grid.Column="0" Grid.Row="1" Minimum="0" 
                               Maximum="{TemplateBinding ScrollViewer.ScrollableWidth}" ViewportSize="{TemplateBinding ScrollViewer.ViewportWidth}" Value="{Binding Path=HorizontalOffset, Mode=OneWay, RelativeSource={RelativeSource Mode=TemplatedParent}}" Visibility="{TemplateBinding ScrollViewer.ComputedHorizontalScrollBarVisibility}" Cursor="Arrow" AutomationProperties.AutomationId="HorizontalScrollBar" />

                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Then override the Style of ScrollViewer with it in the ControlTemplate for DocumentViewer:

   <Style
      x:Key="MyDVStyleExtend"
      BasedOn="{StaticResource {x:Type DocumentViewer}}"
      TargetType="{x:Type DocumentViewer}">

      <Setter Property="Template">                
       <Setter.Value>

          <ControlTemplate TargetType="DocumentViewer">
                        <Border BorderThickness="2,2,2,2"
                    BorderBrush="SlateBlue" Focusable="False">
              <Grid Background="{StaticResource GridBackground}" 
                KeyboardNavigation.TabNavigation="Local">
                <Grid.ColumnDefinitions>                  
                  <ColumnDefinition Width ="*"/>                                    
                </Grid.ColumnDefinitions>                

                <ScrollViewer Style="{StaticResource CustomScrollPresenter}"  Grid.Column ="0" 
                  CanContentScroll="True"
                  HorizontalScrollBarVisibility="Auto"
                  x:Name="PART_ContentHost"
                  IsTabStop="True"/>

              </Grid>
            </Border>
          </ControlTemplate>
        </Setter.Value>
      </Setter>

    </Style>

Then create a function for the "PreviewMouseLeftButtonDown="ScrollContentPresenter_PreviewMouseLeftButtonDown"" attribute stated in the CustomScrollPresenter style.

  private void ScrollContentPresenter_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        e.Handled = true;
    }