maui中实现加载更多 RefreshView跟ListView（1）

效果如图：在这里插入图片描述

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($"Item {i}");}// 通知界面数据源已更新OnPropertyChanged(nameof(Items));}// 数据源的公共属性public ObservableCollection<string> Items => _items;// 是否正在刷新的属性，并使用 SetProperty 方法实现属性更改通知public bool IsRefreshing{get => _isRefreshing;set => SetProperty(ref _isRefreshing, value);}// 刷新命令，绑定到下拉刷新控件public Command RefreshCommand => new Command(async () => await OnRefresh());// 下拉刷新事件处理方法private async Task OnRefresh(){// 开始刷新IsRefreshing = true;// 模拟异步操作（例如，从网络加载数据）await Task.Delay(2000);// 在主线程上更新 UIawait MainThread.InvokeOnMainThreadAsync(() =>{// 添加新的列表项for (int i = 0; i < 10; i++){_items.Add($"New Item {_items.Count}");}// 结束刷新IsRefreshing = false;});}// 列表项即将可见事件处理方法private async void OnItemAppearing(object sender, ItemVisibilityEventArgs e){// 检查是否即将显示最后一个列表项，触发加载更多if (e.Item == _items[_items.Count - 1]){await LoadMoreItems();}}// 加载更多的方法private async Task LoadMoreItems(){// 模拟加载更多数据的异步操作await Task.Delay(2000);// 在主线程上更新 UIawait MainThread.InvokeOnMainThreadAsync(() =>{// 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?.Invoke();OnPropertyChanged(propertyName);return true;}}
}

xaml

<?xml version="1.0" encoding="utf-8" ?>
<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>