WPF框架中异步、多线程、高性能与零拷贝技术应用示例
一、异步编程在WPF中的应用
1. 异步数据加载（避免UI冻结）
// ViewModel中的异步数据加载示例
public class MainViewModel : INotifyPropertyChanged
{private ObservableCollection<string> _items;public ObservableCollection<string> Items{get => _items;set { _items = value; OnPropertyChanged(); }}public async Task LoadDataAsync(){// 显示加载状态IsLoading = true;try{// 模拟耗时操作var data = await Task.Run(() =>{// 这里可以是数据库查询、文件读取或网络请求Thread.Sleep(2000); // 模拟耗时操作return new List<string> { "Item1", "Item2", "Item3" };});Items = new ObservableCollection<string>(data);}catch (Exception ex){// 错误处理MessageBox.Show($"加载数据失败: {ex.Message}");}finally{IsLoading = false;}}private bool _isLoading;public bool IsLoading{get => _isLoading;set { _isLoading = value; OnPropertyChanged(); }}public event PropertyChangedEventHandler PropertyChanged;protected void OnPropertyChanged([CallerMemberName] string propertyName = null){PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));}
}// XAML中的使用
<Window x:Class="WpfAsyncDemo.MainWindow"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"Title="异步加载示例" Height="350" Width="525"><Grid><StackPanel VerticalAlignment="Center" HorizontalAlignment="Center"><ProgressBar IsIndeterminate="{Binding IsLoading}" Width="200" Height="10"/><Button Content="加载数据" Click="LoadData_Click" Margin="0,10"/><ListBox ItemsSource="{Binding Items}" Height="200"/></StackPanel></Grid>
</Window>// 代码后台
public partial class MainWindow : Window
{private readonly MainViewModel _viewModel = new MainViewModel();public MainWindow(){InitializeComponent();DataContext = _viewModel;}private async void LoadData_Click(object sender, RoutedEventArgs e){await _viewModel.LoadDataAsync();}
}
2. 异步文件I/O操作
// 异步读取大文件
public async Task<string> ReadLargeFileAsync(string filePath)
{using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, useAsync: true))using (var reader = new StreamReader(stream)){return await reader.ReadToEndAsync();}
}// 异步写入文件
public async Task WriteLargeFileAsync(string filePath, string content)
{using (var stream = new FileStream(filePath, FileMode.Create, FileAccess.Write, FileShare.None, 4096, useAsync: true))using (var writer = new StreamWriter(stream)){await writer.WriteAsync(content);}
}
二、多线程技术在WPF中的应用
1. 使用BackgroundWorker（传统方式）
// 在ViewModel中使用BackgroundWorker
public class BackgroundWorkerViewModel : INotifyPropertyChanged
{private readonly BackgroundWorker _worker
