我不知道为什么我的 ICollectionView 没有刷新。谁能解释我做错了什么？
我制作了这样的视图模型：
class ViewModel : INotifyPropertyChanged
{
private ObservableCollection<Entity> m_entities = new ObservableCollection<Entity>();
public ICollectionView EntitiesView { get; private set; }
public ICollectionView HighCountView { get; private set; }
public ViewModel()
{
m_entities.Add(new Entity() { Id = 1, Name = "Erik", Description = "The first" });
m_entities.Add(new Entity() { Id = 2, Name = "Olle", Description = "The second" });
m_entities.Add(new Entity() { Id = 3, Name = "Kim", Description = "The last" });
EntitiesView = CollectionViewSource.GetDefaultView(m_entities);
EntitiesView.CurrentChanged += new EventHandler(EntitiesView_CurrentChanged);
HighCountView = new CollectionView(m_entities);
using (HighCountView.DeferRefresh())
{
HighCountView.Filter = e => ((Entity)e).Count > 3;
}
}
private void EntitiesView_CurrentChanged(object sender, EventArgs e)
{
Entity current = EntitiesView.CurrentItem as Entity;
if(current!=null)
{
current.Count++;
HighCountView.Refresh(); // Do I need this line?
OnPropertyChanged("HighCountView"); // or this?
}
}
...在我的窗口中，我将其用作数据上下文，如下所示：
public partial class MainWindow : Window
{
private ViewModel vm = new ViewModel();
public MainWindow()
{
InitializeComponent();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
this.DataContext = vm;
}
}
...我正在像这样在 XAML 代码中进行绑定：
<ListBox Grid.Column="0" x:Name="listView1" DisplayMemberPath="Name" ItemsSource="{Binding EntitiesView}" IsSynchronizedWithCurrentItem="True" />
<ListView Grid.Column="1" x:Name="listView2" DisplayMemberPath="Name" ItemsSource="{Binding HighCountView}" IsSynchronizedWithCurrentItem="True" />
问题是所有三个实体始终显示在 listView2 中，尽管我设置了过滤器属性。为什么？
编辑
为了使示例完整，这里是实体类。
class Entity : INotifyPropertyChanged
{
private int m_id;
public int Id
{
bla bla.....
}
private string m_name;
public string Name
{
bla bla.....
}
private string m_description;
public string Description
{
bla bla.....
}
private int m_count;
public int Count
{
get { return m_count; }
set
{
if (value != m_count)
{
m_count = value;
OnPropertyChanged("Count");
}
}
}
public void Update()
{
Description = "Updated: " + (++Count).ToString() + " times.";
}