过滤一个ObservableCollection？ [英] Filtering an ObservableCollection?

问题描述

当我直接绑定一个ListBox到一个ObservableCollection我得到了我的列表框显示的实时更新，但只要我在混合添加其他LINQ方法我的列表框不再是任何改变的ObservableCollection通知。

When I bind a ListBox directly to an ObservableCollection I get the real-time updates displayed in my ListBox, but as soon as I add other LINQ methods in the mix my ListBox is no longer notified of any changes to the ObservableCollection.

下面，让我说明一个例子;

Here, let me illustrate with an example;

public partial class MainPage : PhoneApplicationPage
{
    ObservableCollection<String> Words = new ObservableCollection<string>();

    public MainPage()
    {
        InitializeComponent();
        listBox1.ItemsSource = Words;
    }

    private void AddButton_Click(object sender, RoutedEventArgs e)
    {
        Words.Add(DateTime.Now.ToString());
    }
}

在这里，我添加了一个按钮和一个列表框，以一个简单的页面，然后点击按钮，使新项目在ListBox中立即出现。

Here I've added a Button and a ListBox to a simple Page, and clicking the button makes the new item appear immediately in the ListBox.

不过，如果我从更改

        listBox1.ItemsSource = Words;

到

        listBox1.ItemsSource = Words.Where(w => w.Contains(":"));

ListBox中不再更新。

the ListBox is no longer updated.

如何添加一个过滤器我的ObservableCollection和列表框之间，仍然得到它，而无需重新设置.ItemsSource更新？

How can I add a "filter" between my ObservableCollection and the ListBox, and still get it to update without having to set the .ItemsSource again?

推荐答案

尝试使用CollectionViewSource是这样的：

Try using the CollectionViewSource like this:

WordsView = new CollectionViewSource();
WordsView.Filter += Words_Filter;
WordsView.Source = Words;

// ...
void Words_Filter(object sender, FilterEventArgs e)
{
    if (e.Item != null)
        e.Accepted = ((string)e.Item).Contains(":");
}

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