Make ScrollViewer fill dynamic area

Question

In the example below I cannot get the ScrollViewer to fill the space available, The height is unknown due to the dynamic content above but is there no way it can fill the space available instead of over running?

   <Grid x:Name="Main" Height="200" MaxHeight="200">
      <StackPanel>
         <Grid x:Name="MainContent" Height="170" MaxHeight="170">
            <StackPanel>
               <TextBlock FontSize="24" Text="Dynamic data "/>
               <TextBlock FontSize="24" Text="height "/>
               <TextBlock FontSize="24" Text="unknown... "/>
               <Grid x:Name="Results" Background="Red">
                  <ScrollViewer>
                     <StackPanel>
                        <TextBlock FontSize="24" Text="Result set... 0"/>
                        <TextBlock FontSize="24" Text="Result set... 1"/>
                        <TextBlock FontSize="24" Text="Result set... 2"/>
                        <TextBlock FontSize="24" Text="Result set... 3"/>
                     </StackPanel>
                  </ScrollViewer>
               </Grid>
            </StackPanel>
         </Grid>
         <Grid x:Name="Nav">
            <Button HorizontalAlignment="Left" Content="Back"/>
            <Button HorizontalAlignment="Right" Content="Forward"/>
         </Grid>
      </StackPanel>
   </Grid>

Answer 1

in MainContent Grid use DockPanel instead of StackPanel with LastChildFill=True, something like this:

<Grid x:Name="MainContent" Height="170" MaxHeight="170">
    <DockPanel LastChildFill="True">
        <TextBlock DockPanel.Dock="Top" FontSize="24" Text="Dynamic data "/>
        <TextBlock DockPanel.Dock="Top" FontSize="24" Text="height "/>
        <TextBlock DockPanel.Dock="Top" FontSize="24" Text="unknown... "/>
        <Grid x:Name="Results" Background="Red">
            <ScrollViewer>
                <StackPanel>
                    <TextBlock FontSize="24" Text="Result set... 0"/>
                    <TextBlock FontSize="24" Text="Result set... 1"/>
                    <TextBlock FontSize="24" Text="Result set... 2"/>
                    <TextBlock FontSize="24" Text="Result set... 3"/>
                </StackPanel>
            </ScrollViewer>
        </Grid>               
    </DockPanel>
</Grid>

then last element of DockPanel will adjust itself to available space