WPF中使用INotifyPropertyChanged绑定系统相关信息

Question

我希望使用 MVVM 绑定和 在 WPF XAML 中列出 临时文件 INotifyPropertyChanged.

视图模型是 TempViewModel.cs

class TempViewModel : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public List<FileInfo> CacheFiles { get { string path = Environment.GetFolderPath(Environment.SpecialFolder.InternetCache); System.IO.DirectoryInfo di = new DirectoryInfo(path); return di.GetFiles().ToList(); } } }

临时文件夹中的文件可能会不时发生变化。我需要自动更新它，只要在 XAML UI
中使用 INotifyPropertyChanged 在 Temp 文件夹中更新文件
如何在 XMAL 中绑定它？

MainWindow.xaml

<Window x:Class="Binding.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"> <Grid> <ListBox Name="LstProduct" ItemsSource="{Binding CacheFiles}" ScrollViewer.HorizontalScrollBarVisibility="Disabled"> <ListBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding Path=FullName}"/> </DataTemplate> </ListBox.ItemTemplate> </ListBox> </Grid> </Window>

MainWindow.xaml.cs

public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); Loaded += new RoutedEventHandler(MainWindow_Loaded); } void MainWindow_Loaded(object sender, RoutedEventArgs e) { this.DataContext = new TempViewModel(); } }

我无法在 UI 中获取更新的文件名列表。请帮助我，如何在临时文件夹中添加或删除文件时更新 UI？

Answer 1

使用 FileSystemWatcher(see the docs for how to use it) 并订阅其中一个事件。在该处理程序中，使用 "CacheFiles" 调用 PropertyChanged 事件以向 UI 发送信号以重新获取 CacheFiles 属性.

您当然可以通过 ObservableCollection 和手动 adding/removing 条目对此进行改进，但我描述的方式应该有效。

Answer 2

您应该使用 FileSystemWatcher 和 Changed event。例如，当 FileSystemWatcher 引发 Changed 事件时，您的事件处理程序应该通过引发 PropertyChanged

来更改 CacheFile 属性

Answer 3

答案是FileSystemWatcher

你应该修改你的TempViewModel.cs

class Cleaner : INotifyPropertyChanged
{

    public event PropertyChangedEventHandler PropertyChanged;

    private List<KeyValuePair<string, ulong>> _memoryPool = new List<KeyValuePair<string, ulong>>();
    public List<KeyValuePair<string, ulong>> MemoryPool
    {
        get { return _memoryPool; }
        set
        {
            _memoryPool = value;
            if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("MemoryPool"));
        }
    }


    private void watch()
    {
        FileSystemWatcher watcher = new FileSystemWatcher();
        watcher.Path = Environment.GetFolderPath(Environment.SpecialFolder.InternetCache);
        watcher.NotifyFilter = NotifyFilters.LastWrite;
        watcher.Filter = "*.*";
        watcher.Changed += new FileSystemEventHandler(OnChanged);
        watcher.EnableRaisingEvents = true;
    }

    private void OnChanged(object source, FileSystemEventArgs e)
    {
        UpdateCollection();
    }

    private void UpdateCollection()
    {
        string path = Environment.GetFolderPath(Environment.SpecialFolder.InternetCache);;
        System.IO.DirectoryInfo di = new DirectoryInfo(path);
        CacheFiles = di.GetFiles().ToList();
    }

    public Cleaner()
    {
        UpdateCollection();
        watch();
    }
}

WPF中使用INotifyPropertyChanged绑定系统相关信息

Bind System related information in WPF using INotifyPropertyChanged

c#

wpf

xaml

mvvm

inotifypropertychanged