Get selected item FlexLayout BindableLayout

I have code:

<ScrollView>
    <FlexLayout AlignContent="Start" AlignItems="Center" AlignSelf="Start" x:Name="listStudios"
                Direction="Row" JustifyContent="SpaceEvenly" Wrap="Wrap" BackgroundColor="White" HorizontalOptions="Fill" VerticalOptions="Fill">
        <BindableLayout.ItemTemplate>
            <DataTemplate>
                <customControls:ButtonStates Text="{Binding EnglishName}" TextColor="Black" BackgroundColor="Transparent" BorderColor="#108FE6" BorderWidth="2" HeightRequest="50" FontAttributes="Bold" ButtonString="{Binding ID}"/> 
            </DataTemplate>
        </BindableLayout.ItemTemplate>
    </FlexLayout>
</ScrollView>

How i can get selected item? I can't do it through Command. Maybe are there other ways?
I want to make it possible to get ButtonString from buttons.