MainViewModel.cs

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

namespace HC
{
    
    public class MainViewModel //:INotifyPropertyChanged
    {
        /*
        private bool _isBusy;
        private const int PageSize = 10;
        data2 _dataService = new data2();

        public InfiniteScrollCollection<string> Items { get; }

        public bool IsBusy
        {
            get => _isBusy;
            set
            {
                _isBusy = value;
                OnPropertyChanged();
            }
        }

        public MainViewModel()
        {
            Items = new InfiniteScrollCollection<string>
            {
                OnLoadMore = async () =>
                {
                    IsBusy = true;

                    // load the next page
                    var page = Items.Count / PageSize;

                    var items = await _dataService.GetItemsAsync(page, PageSize);

                    IsBusy = false;

                    // return the items that need to be added

                    return items;
                },
                OnCanLoadMore = () =>
                {
                    return Items.Count < 44;
                }
            };

            DownloadDataAsync();
        }

        private async Task DownloadDataAsync()
        {
            var items = await _dataService.GetItemsAsync(PageIndex: 0, PageSize: PageSize);

            Items.AddRange(items);
        }

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
        */
    }
}