LoadMoreOnBottom.cs

using System;

using Xamarin.Forms;
using System.Collections.ObjectModel;
using System.Threading.Tasks;

namespace LoadMoreBottom
{
	public class App : Application
	{
		ObservableCollection<string> Items;
		bool isLoading;
		Page page;
		public App ()
		{
			Items = new ObservableCollection<string> ();
			var listview = new ListView ();

			listview.ItemsSource = Items;
			listview.ItemAppearing += (sender, e) => 
			{
				if(isLoading || Items.Count == 0)
					return;

				//hit bottom!
				if(e.Item.ToString() == Items[Items.Count - 1])
				{
					LoadItems();
				}
			};

			// The root page of your application
			page = new ContentPage {
				Content = new StackLayout {
					VerticalOptions = LayoutOptions.Center,
					Children = {
						listview
					}
				}
			};

			MainPage = new NavigationPage (page);

			LoadItems ();


		}

		private async Task LoadItems()
		{
			isLoading = true;
			page.Title = "Loading";

			//simulator delayed load
			Device.StartTimer (TimeSpan.FromSeconds (2), () => {
				for (int i = 0; i < 20; i++) {
					Items.Add (string.Format("Item {0}", Items.Count));
				}
				page.Title = "Done";
				isLoading = false;
				//stop timer
				return false;
			});
		}

		protected override void OnStart ()
		{
			// Handle when your app starts
		}

		protected override void OnSleep ()
		{
			// Handle when your app sleeps
		}

		protected override void OnResume ()
		{
			// Handle when your app resumes
		}
	}
}

It appears that when doing a rapid motion scroll - the 'if(e.Item.ToString() == Items[Items.Count - 1])' part doesn't seem to evaluate to true... any clue as to why?