How to make wpf row shrink to fit contents

Question

I have a grid with two rows plus a grid splitter. I want the top row's height to be as small as possible by default (in this case, the height of the button) The bottom row should expand to take up the remaining space in the grid. I want the grid splitter there to allow the user to change the size as needed.

<Grid>
    <Grid.RowDefinitions>
        <RowDefinition />
        <RowDefinition Height="5" />
        <RowDefinition Height="*" />
    </Grid.RowDefinitions>

    <Button Grid.Row="0" Content="A little old button" VerticalAlignment="Center" />
    <GridSplitter Grid.Row="1" Background="Black" HorizontalAlignment="Stretch" />
    <TextBlock Grid.Row="2" TextWrapping="Wrap">
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    </TextBlock>
</Grid>

How should I setup the xaml?

Answer 1

<RowDefinition Height="Auto" /> 

should do it.