maui中实现加载更多 RefreshView跟ListView（1）

效果如图：

MainPage.xaml.cs:

using System;using System.Collections.ObjectModel;using System.Threading.Tasks;using Microsoft.Maui.Controls;using Microsoft.Maui.Controls.Xaml;using System.ComponentModel;using System.Runtime.CompilerServices;namespace fenye{// 标记 XAML 编译选项[XamlCompilation(XamlCompilationOptions.Compile)]public partial class MainPage : ContentPage{// 数据源，用于存储列表项的集合private ObservableCollection<string> _items;// 是否正在刷新的标志private bool _isRefreshing;// 构造函数，初始化页面public MainPage(){InitializeComponent();BindingContext = this;// 初始化数据源并填充一些初始数据_items = new ObservableCollection<string>();for (int i = 0; i < 20; i++){_items.Add($"Item {i}");}// 通知界面数据源已更新OnPropertyChanged(nameof(Items));}// 数据源的公共属性public ObservableCollection<string> Items => _items;// 是否正在刷新的属性，并使用 SetProperty 方法实现属性更改通知public bool IsRefreshing{get => _isRefreshing;set => SetProperty(ref _isRefreshing, value);}// 刷新命令，绑定到下拉刷新控件public Command RefreshCommand => new Command(async () => await OnRefresh());// 下拉刷新事件处理方法private async Task OnRefresh(){// 开始刷新IsRefreshing = true;// 模拟异步操作（例如，从网络加载数据）await Task.Delay(2000);// 在主线程上更新 UIawait MainThread.InvokeOnMainThreadAsync(() =>{// 添加新的列表项for (int i = 0; i {// 添加更多新的列表项for (int i = 0; i < 10; i++){_items.Add($"New Item {_items.Count}");}IsRefreshing = false;});}// 通用方法，用于设置属性并触发属性更改通知protected bool SetProperty<T>(ref T backingStore, T value,[CallerMemberName] string propertyName = "",Action onChanged = null){if (EqualityComparer<T>.Default.Equals(backingStore, value))return false;backingStore = value;onChanged" />xaml 
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:d="http://schemas.microsoft.com/dotnet/2021/maui/design" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" BackgroundColor="{DynamicResource PageBackgroundColor}" x:Class="fenye.MainPage"><RefreshView IsRefreshing="{Binding IsRefreshing}" Command="{Binding RefreshCommand}"><StackLayout Margin="10"><ListView ItemsSource="{Binding Items}" ItemAppearing="OnItemAppearing"><ListView.ItemTemplate><DataTemplate><TextCell Text="{Binding .}" /></DataTemplate></ListView.ItemTemplate></ListView></StackLayout></RefreshView></ContentPage>