How do I bind height of element in a grid to the actual height of a grid.row

Question

I have a Windows 8.1 universal app that I am working on for a client. The client wants a part of a flyout to be the same height of a different part of that same flyout. The flyout uses a datatemplate and that datatemplate contains a grid of three rows and two columns. An element within a scrollviewer in row 0, column 1 (row span 3) needs to be the same height as the first row in the grid. Is there a way to achieve this?

I cannot get the grid with x:Name because it is within a datatemplate. The client insists the area indicated by the red arrow is the same height as the orange area at the top of the flyout AND it must be in that scrollable area.

Any ideas?

Thanks,
Zach

Edit: Here is the xaml.

   <DataTemplate x:Name="MultiselectFlyout">
        <Grid HorizontalAlignment="Stretch" VerticalAlignment="Stretch"  Background="White">
            <Grid.RowDefinitions>
                <RowDefinition Height=".25*" />
                <RowDefinition Height=".18*" />
                <RowDefinition Height="*" />
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*" />
                <ColumnDefinition Width=".22*" />
            </Grid.ColumnDefinitions>
            <Border Background="Gray" Grid.Row="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
                <TextBlock Text="{Binding SelectedName, Mode=OneWay}" FontSize="34" FontFamily="{StaticResource GothamMedium}" TextAlignment="Center" Foreground="White" VerticalAlignment="Center" HorizontalAlignment="Center"/>
            </Border>
            <Border Grid.Row="1" Grid.ColumnSpan="2" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Background="Transparent">
                <Image Source="../Assets/dropshadow_B.png" Height="150" Margin="0,-110,0,0" Opacity=".3" Stretch="Fill" VerticalAlignment="Top" HorizontalAlignment="Stretch"/>
            </Border>
            <Border Background="{StaticResource PrimaryColor}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
                <TextBlock Foreground="White" Padding="0" TextAlignment="Center" VerticalAlignment="Center">
                    <Run Text="{Binding Title}" FontSize="44" FontFamily="{StaticResource GothamMedium}"/>
                    <LineBreak/>
                    <Run Text="{Binding Subtitle[0]}" FontSize="28" FontFamily="{StaticResource GothamLight}"/>
                </TextBlock>
            </Border>
            <Grid x:Name="ImageSwap" Grid.Row="2" Background="White">
                <Border Background="Transparent" BorderBrush="Gray" BorderThickness="0,0,1,0">
                    <Image Source="{Binding BottomImage, Mode=OneWay}" Stretch="Uniform" ImageOpened="Image_Opened"/>
                </Border>
                <Border Background="Transparent" BorderBrush="Gray" BorderThickness="0,0,1,0">
                    <Image Source="{Binding TopImage, Mode=OneWay}" Opacity="{Binding TopImgVisibility, Mode=OneWay}" Stretch="Uniform" ImageOpened="Image_Opened"/>
                </Border>
            </Grid>
            <ScrollViewer Grid.Row="1" Grid.RowSpan="2" Grid.Column="1" Background="White" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" VerticalScrollBarVisibility="Hidden" VerticalScrollMode="Enabled" Loaded="ScrollViewer_Loaded" Tapped="ScrollViewer_Tapped">
                <ItemsControl ItemsSource="{Binding Colors, Mode=OneWay}" ItemTemplateSelector="{StaticResource DividerOrImageSelector}" Background="White" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
                    <ItemsControl.ItemsPanel>
                        <ItemsPanelTemplate>
                            <StackPanel Orientation="Vertical" HorizontalAlignment="Stretch" VerticalAlignment="Top"/>
                        </ItemsPanelTemplate>
                    </ItemsControl.ItemsPanel>
                </ItemsControl>
            </ScrollViewer>
            <Border Grid.Column="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Background="LightGray">
                <Viewbox StretchDirection="DownOnly" Margin="0">
                    <TextBlock FontFamily="{StaticResource GothamMedium}" Foreground="Black" FontSize="22" TextAlignment="Center" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
                        <Run Text="SCROLL"/><LineBreak /><Run Text="TO SEE ALL"/><LineBreak /><Run Text="THE COLORS"/>
                    </TextBlock>
                </Viewbox>
            </Border>
        </Grid>
    </DataTemplate>

Answer 1

Try this:

<RowDefinition x:Name="row">
<Button Height="{Binding Height,ElementName="row"}">