public partial class WebViewSelectorGenerator : ContentPage
    {

        public List<SlotsButtons> slots;

        private SlotsButtons _selectedItem;

        public SlotsButtons SelectedItem
        {
            get
            {

                return _selectedItem;

            }
            set
            {
                _selectedItem = value;

                if (_selectedItem == null)
                    return;

                // now here you have an instance of SlotsButtons
                // you can do :
                var id = _selectedItem.ID;
                // store your id in a page variable for example and later on do the logic
            }
        }

    public WebViewSelectorGenerator()
    {
        [...]

        slots = new List<SlotsButtons>();
        slots.Add(new SlotsButtons { Text = "1" });
        slots.Add(new SlotsButtons { Text = "2" });

        BindingContext = this;
    }
[...]
}