UWP Grid and/or StackPanel with 50% height
<p>I want to arrange 2 Grids (or StackPanels) incl. a Scrollviewer vertical.
Each of them should be 50% of the device's height. Or, to be more precisely: They are in a container and their height should be 50% of the height of that container.
As far as I know I can set the height in Pixels, to "auto" and to "*", but not to percentages.</p>

<p>What technique should be used to reach that goal?</p>

<p>My Code so far:</p>

<pre><code>&lt;Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"&gt;
        &lt;Pivot Title="Pivot" &gt;
            &lt;PivotItem Header="Start"&gt;
                &lt;Grid/&gt;
            &lt;/PivotItem&gt;
            &lt;PivotItem Header="Baustellenbegehung"&gt;
                &lt;Grid/&gt;
            &lt;/PivotItem&gt;
            &lt;PivotItem Header="Mangelanzeige"&gt;
                &lt;Grid&gt;
                    &lt;Grid.RowDefinitions&gt;
                        &lt;RowDefinition Height="*"/&gt;
                        &lt;RowDefinition Height="*"/&gt;
                    &lt;/Grid.RowDefinitions&gt;
                    &lt;StackPanel Grid.Row="0" Orientation="Vertical"&gt;
                        &lt;ScrollViewer&gt;
                            &lt;StackPanel Orientation="Vertical"&gt;
                                &lt;TextBlock Text="Aktuelle Mangelanzeigen" /&gt;
                                &lt;ListView Name="lstMangelanzeigenAktiv" /&gt;
                            &lt;/StackPanel&gt;
                        &lt;/ScrollViewer&gt;
                    &lt;/StackPanel&gt;
                    &lt;StackPanel Grid.Row="1" Orientation="Vertical"&gt;
                        &lt;ScrollViewer&gt;
                            &lt;StackPanel&gt;
                                &lt;TextBlock Text="Archiv Mangelanzeigen" /&gt;
                                &lt;ListView Name="lstMangelanzeigenArchiv" /&gt;
                            &lt;/StackPanel&gt;
                        &lt;/ScrollViewer&gt;
                    &lt;/StackPanel&gt;
                &lt;/Grid&gt;
            &lt;/PivotItem&gt;
            &lt;PivotItem Header="Zustandsfeststellungsprotokoll"&gt;
                &lt;Grid/&gt;
            &lt;/PivotItem&gt;
        &lt;/Pivot&gt;

    &lt;/Grid&gt;
</code></pre>

<p>EDIT:</p>

<p>I stripped the code down and added .5* as suggested, but when I fill the ListView I cannot scroll in them:</p>

<pre><code>&lt;Grid&gt;
    &lt;Grid.RowDefinitions&gt;
        &lt;RowDefinition Height=".5*"/&gt;
        &lt;RowDefinition Height=".5*"/&gt;
    &lt;/Grid.RowDefinitions&gt;
    &lt;StackPanel Grid.Row="0" Orientation="Vertical"&gt;
        &lt;ScrollViewer&gt;
            &lt;StackPanel Orientation="Vertical"&gt;
                &lt;TextBlock Text="Aktuelle Mangelanzeigen" /&gt;
                &lt;ListView Name="lstMangelanzeigenAktiv" /&gt;
            &lt;/StackPanel&gt;
        &lt;/ScrollViewer&gt;
    &lt;/StackPanel&gt;
    &lt;StackPanel Grid.Row="1" Orientation="Vertical"&gt;
        &lt;ScrollViewer&gt;
            &lt;StackPanel&gt;
                &lt;TextBlock Text="Archiv Mangelanzeigen" /&gt;
                &lt;ListView Name="lstMangelanzeigenArchiv" /&gt;
            &lt;/StackPanel&gt;
        &lt;/ScrollViewer&gt;
    &lt;/StackPanel&gt;
&lt;/Grid&gt;
</code></pre>

<p>EDIT 2:
This is a screenshot of my current version.
I added 20 items to both ListViews and I expected to have 2 scrollbars (one per ListView):
<a href="https://i.stack.imgur.com/fm1cY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/fm1cY.png" alt="enter image description here"></a></p>