public MainVM()
        {
            var items = new List <Item>();

            items.Add(new Item {
                Title = "Test1"
            });
            items.Add(new Item {
                Title = "Test2"
            });
            items.Add(new Item {
                Title = "Test3"
            });
            Items = new ObservableRangeCollection <ItemVM>();
            foreach (var item in items)
            {
                var itemVM = new ItemVM(item);
                itemVM.ButtonCommand = new Command <ItemVM>(async(obj) => await ButtonActionAsync(obj));
                Items.Add(itemVM);
            }
        }
 private async Task ButtonActionAsync(ItemVM obj)
 {
     await Application.Current.MainPage.DisplayAlert("Button Click", "item " + obj.TitleItem + " was clicked", "ok");
 }