How to implement scrolling in a RichTextBlock in Windows Phone

Question

I have a Windows Phone Universal app that has a RichTextBlock which loads its content dynamically. Sometimes the content is short and sometimes its too long to fit in a page; hence, I would like the RichTextBlock to expand dynamically and give the user the ability to scroll to see the entire content.

I looked around (here and other places) for piece of code that achieves this, but was not very successful. The closest I got was the following code that doesn't work:

<ScrollViewer Width="Auto" Height="Auto" VerticalScrollBarVisibility="Visible" VerticalScrollMode="Enabled">
    <RichTextBlock FontSize="20" Foreground="White" IsTextSelectionEnabled="False" Margin="12,0" ScrollViewer.VerticalScrollBarVisibility="Visible">
        <Paragraph>
            Place a very long text here.
        </Paragraph>
    </RichTextBlock>
</ScrollViewer>

Any help is appreciated.

Answer 1

This will work:

<ScrollViewer Height="150" Width="150">
    <RichTextBlock>
        <Paragraph>This is my RichTextblock</Paragraph>
    </RichTextBlock>
</ScrollViewer>

The trick here is to fix the Height and/or Width (depending on which direction you want to scroll).

Back to the example in the question; all it needs is an absolute value; e.g., Height="480":

<ScrollViewer Width="Auto" Height="480" VerticalScrollBarVisibility="Visible" VerticalScrollMode="Enabled">
    <RichTextBlock FontSize="20" Foreground="White" IsTextSelectionEnabled="False" Margin="12,0" ScrollViewer.VerticalScrollBarVisibility="Visible">
        <Paragraph>
            Place a very long text here.
        </Paragraph>
    </RichTextBlock>
</ScrollViewer>