Accessing TLISTVIEW data programmatically

I am trying to access TListview members data I have created in LiveBindings programmatically and cant figure out it. 

I created a live binding to a rest field called rec_id and  If use clicks on a TListView item I need to get the rec_id of the item they have clicked for further work, rec_id is a non visible field.

This is what I have now. How do I get rec_id data?

LiveBinding(LinkPropertytoFieldrec_id)  FDMemTable id ---> ListView2 rec_id

procedure TForm1.ListView2ButtonClick(const Sender: TObject;

const AItem: TListViewItem; const AObject: TListItemSimpleControl);

var

Rec_id_string : String;

begin

Rec_id_string := AItem ???? rec_id

end;