像INotifyCollectionChanged火灾的xml文件改变

Question

这是可能的实现INotifyCollectionChanged或其它接口等的IObservable以使得能够结合来自该文件的XML文件滤波的数据改变？我看到与文件的更改属性或收藏，但什么例子？

我有代码来过滤和绑定的XML数据给列表框：

XmlDocument channelsDoc = new XmlDocument();
channelsDoc.Load("RssChannels.xml");
XmlNodeList channelsList = channelsDoc.GetElementsByTagName("channel");
this.RssChannelsListBox.DataContext = channelsList;

Answer 1

尝试使用FileSystemWatcher的

    private static void StartMonitoring()
    {
        //Watch the current directory for changes to the file RssChannels.xml
        var fileSystemWatcher = new FileSystemWatcher(@".\","RssChannels.xml");

        //What should happen when the file is changed
        fileSystemWatcher.Changed += fileSystemWatcher_Changed;

        //Start watching
        fileSystemWatcher.EnableRaisingEvents = true;
    }

    static void fileSystemWatcher_Changed(object sender, FileSystemEventArgs e)
    {
        Debug.WriteLine(e.FullPath + " changed");
    }

Answer 2

您将必须实现INotifyCollectionChanged你自己，看文件系统变化System.IO使用FileSystemWatcher类

Answer 3

在XmlDocument已经引发NodeChanged事件。如果您使用的XmlDataProvider作为绑定源，它监听NodeChanged事件和刷新绑定。如果你改变它的Document性能也刷新绑定。再加上与FileSystemWatcher，你对你的方式。

一个简单的例子：

<Window x:Class="WpfApplication18.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <Window.Resources>
        <XmlDataProvider x:Key="Data" XPath="/Data">
            <x:XData>
                <Data xmlns="">
                    <Channel>foo</Channel>
                    <Channel>bar</Channel>
                    <Channel>baz</Channel>
                    <Channel>bat</Channel>
                </Data>
            </x:XData>
        </XmlDataProvider>
    </Window.Resources>
    <StackPanel Margin="50">
        <ListBox ItemsSource="{Binding Source={StaticResource Data}, XPath=Channel}" />
        <Button Margin="10" 
                Click="ReloadButton_Click">Reload</Button>
        <Button Margin="10"
                Click="UpdateButton_Click">Update</Button>
    </StackPanel>
</Window>

在事件处理程序：

private void ReloadButton_Click(object sender, RoutedEventArgs e)
{
    XmlDocument d = new XmlDocument();
    d.LoadXml(@"<Data xmlns=''><Channel>foobar</Channel><Channel>quux</Channel></Data>");
    XmlDataProvider p = Resources["Data"] as XmlDataProvider;
    p.Document = d;
}

private void UpdateButton_Click(object sender, RoutedEventArgs e)
{
    XmlDataProvider p = Resources["Data"] as XmlDataProvider;
    XmlDocument d = p.Document;
    foreach (XmlElement elm in d.SelectNodes("/Data/Channel"))
    {
        elm.InnerText = "Updated";
    }
}