Question

As I need to display long text strings in one of my WP7 project, I added Alex Yakhnin’s ScrollableTextBlock control to it.

It’s working as expected, but I need to scroll the textblock automatically on certain user interaction, but the control doesn’t support ScrollToVerticalOffset out of the box and I have no idea how to go about it.

I guess removing the element and adding new one would do it, but I think that’s doing bit too much for such a simple task.

Answer 1

One kind of ugly workaround is to add a Load-event to the ScrollViewer. When the event fires, fetch the sender (which is the ScrollViewer, duh!) and store it in a class-level variable. This way you have access to it in other methods and you can use the ScrollToVerticalOffset-method.

XAML

<PhoneApp1:ScrollableTextBlock x:Name="TextBlockOne" Margin="0,0,-12,0">
    <PhoneApp1:ScrollableTextBlock.Style>
        <Style TargetType="PhoneApp1:ScrollableTextBlock" >
            <Setter Property="Foreground" Value="{StaticResource PhoneForegroundBrush}"/>
            <Setter Property="Background" Value="Transparent"/>
            <Setter Property="FontSize" Value="{StaticResource PhoneFontSizeMedium}"/>
            <Setter Property="Padding" Value="0"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="PhoneApp1:ScrollableTextBlock">
                        <ScrollViewer Foreground="{TemplateBinding Foreground}"
                                      Background="{TemplateBinding Background}" 
                                      BorderBrush="{TemplateBinding BorderBrush}"
                                      BorderThickness="{TemplateBinding BorderThickness}" 
                                      Padding="{TemplateBinding Padding}"
                                      Loaded="ScrollViewer_Loaded">
                            <StackPanel Orientation="Vertical" x:Name="StackPanel" />
                        </ScrollViewer>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </PhoneApp1:ScrollableTextBlock.Style>
</PhoneApp1:ScrollableTextBlock>

C#

private ScrollViewer _scroller;

private void ScrollViewer_Loaded(object sender, System.Windows.RoutedEventArgs e)
{
    _scroller = sender as ScrollViewer;
}

private void SomeMethod()
{
    _scroller.ScrollToVerticalOffset(200d);
}

I know it’s probably not the nicest solution but it works. Hope this helps!