Getting ViewCell content in ListView.ItemSelected

I'm having an issue with ListView in XAML.
I try to achieve a ExpandableList with opening animation. For this I wanted to use a ListView and StackLayout.

In the ItemSelected event, I would like to add values to the stacklayout and then increase the Height animated. But how do I get a reference to the ViewCell?

And further, is there a way to get the calculated height of the stacklayout and use LayoutTo to this value?

Thanks