Example how to implement Infinite Scroll in Xamarin.Forms applications. - http://julianocustodio.com/listview-infinite-scroll

MainViewModel.cs

using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Threading.Tasks;
using Xamarin.Forms.Extended;

namespace InfiniteScrollDemo
{
    public class MainViewModel : INotifyPropertyChanged
    {
        private const int PageSize = 8;
        private bool _isBusy;
        readonly Service _service = new Service();
        public InfiniteScrollCollection<string> Items { get; }

        
    }
}