How to set a RichTextBox in Silverlight 4 to fit it's parent height and maintain it on resize?

I am having hard times figuring this out. Here is what I need:

<StackPanel x:Name="container" VerticalAlignment="Stretch">
     <RichTextBox Height="???" />
</StackPanel>

Basically what I know I can do is to bind RichTextBox Height to it's parent's height ( Height="{Binding ElementName=container, Path=ActualHeight}". Unfortunately this only works on load, because as it seems ActualHeight and ActualWidth don't notify for changes.

So what is the best way in Silverlight 4 to tell RichTextBox or TextBlock, it doesn't matter, to fill it's parent height, and maintain scrollbar if it's content height is bigger. Is the only way to bind some Resize events and maintain the height explicitly? That seems really ugly to me? Have anybody had this problem as well?

Any resources or informatio开发者_StackOverflow中文版n is highly appreciated! Thanks.

---

Ivan,

The best way to solve this is to use a Grid as the parent for the RickTextBox, instead of a StackPanel. By default, a Grid will "Strectch" its content to take up all of the available space. A StackPanel will only Stretch its content in one diminsion.

As an example, paste the following XAML into my XamlViewer to see the difference:

<UserControl
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition />
            <RowDefinition />
        </Grid.RowDefinitions>
        <StackPanel Grid.Row="0">
            <RichTextBox
                Foreground="Blue" FontSize="24" Background="Yellow">
                <Paragraph>RichTextBox inside a StackPanel</Paragraph>
            </RichTextBox>
        </StackPanel>
        <Grid Grid.Row="1">
            <RichTextBox
                Foreground="Blue" FontSize="24" Background="Tan">
                <Paragraph>RichTextBox inside a Grid</Paragraph>
            </RichTextBox>
        </Grid>
    </Grid>
</UserControl>

Good luck,
Jim McCurdy, Face to Face Software and YinYangMoney