Align ListView items to bottom of screen when few items

I'd like to have a ListView that starts showing its elements from the bottom up, so that elements are displayed at the bottom of the ListView when there are few items. See the image for explanation. Is this possible to do without having to set the HeightRequest of the ListView manually? (And if setting the HeightRequest manually is required, how can I compute the height of the ListView's child elements when I'm using HasUnevenRows=true?)

Here's how I want it to look (few items to the left, many items to the right);

For reference, here is the way ListView normally works when there are few items: