WPF ScrollViewer Size

See more:

WPF

I'm having an issue with having a scrollviewer size itself.

I have the following xaml:

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

    <Grid Grid.Row="0" Grid.Column="0">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="*" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>

        <!-- record number panel -->
        <Border x:Name="borderLeftColHeader" Grid.Row="0" >
            <!-- content stuff here -->
        </Border>

        <!-- QUESTIONS LIST -->
        <Grid Grid.Row="1" x:Name="gridScrollView" Margin="0,0,5,0" >
            <ScrollViewer x:Name="svQuestions" VerticalScrollBarVisibility="Auto" 
                          Height="{Binding Path=ActualHeight, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Grid}}" >
				
                <!-- this grid is filled in code-behind when the 
                parent user control is instantiated - can have 1-n 
                children -->
                <Grid x:Name="gridQuestions" />
				
            </ScrollViewer>
        </Grid>

        <!-- QUESTION BUTTONS ROW 1 -->
        <Grid Grid.Row="2" Margin="0,0,5,0" >
            <!-- content stuff here -->
        </Grid>
        <!-- QUESTION BUTTONS ROW 2 -->
        <Grid Grid.Row="3" Margin="0,5,0,0">
            <!-- content stuff here -->
        </Grid>
    </Grid>
</Grid>

My problem is that if I specifically set the height of the scrollviewer, it displays as expected.

If I used the binding indicated above (Path=ActualHeight, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Grid}), it uses the ActualHeight of its parent grid which is always 0.

I also tried binding to the grid's element name (using the same Path=ActualHeight).

I also tried adding SizeChanged and UpdatedLayout event handlers to the parent user control and all related elements so I could inspect the ActualHeight of the parent grid (gridScrollView) in the debugger, and it's always 0.

I'm out of ideas. What do I need to do to ensure that the gridScrollView.ActualHeight gets set to something useful, preferably when the user control gets instantiated?