Build an Alphabet listview sort with Pan Gesture

Hi all,

I'm implement a new listview with Alphabet sort pane in the right screen. For example, that sort pane have A-Z chars. When I pan at A, the listview will sort start with A letter.

I called it listview but it's totally made from stacklayout which put in the Scrollview because of complex requirement from the Customer, so I cannot use the native listview control.

My question is, when I'm doing Pan gesture with that Alphabet, how can I know that I'm running at the A letter or B, C letter?

The next question is, how to scroll to specific item in the StackLayout (this stacklayout is put inside a ScrollView) ?

Do you have any idea about those?

Thank you so much,