Question

我是ICollectionView的新手，我正在尝试过滤对象列表。

这是我的ViewModel：

public class ViewModel : INotifyPropertyChanged
{
    private ObservableCollection<RevitFamily> _myData;
    public ObservableCollection<RevitFamily> MyData
    {
        get { return _myData; }
    }

    string searchName = string.Empty;
    ObservableCollection<string> searchKeywords = new ObservableCollection<string>();
            public string SearchName
    {
        get { return searchName; }
        set
        {
            searchName = value;
            myDataView.Filter = FilterName;
            OnPropertyChanged("SearchName");
        }
    }
    public ObservableCollection<string> SearchKeywords
    {
        get { return searchKeywords; }
        set
        {
            searchKeywords = value;
            myDataView.Filter = FilterName;
            OnPropertyChanged("SearchKeywords");
        }
    }
    ICollectionView myDataView;
    public ViewModel()
    {
        _myData = new ObservableCollection<RevitFamily>();
        myDataView = CollectionViewSource.GetDefaultView(_myData);
        //when the current selected changes store it in the CurrentSelectedPerson
        myDataView.CurrentChanged += delegate
        {
            //stores the current selected person
            CurrentSelectedFamily = (RevitFamily)myDataView.CurrentItem;
        };
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

当我在ObservableCollection＆＃34; SearchKeywords＆＃34;中添加项目时，列表已正确更新，但通知＆＃34; OnPropertyChanged＆＃34;不打电话。我怎么能这样做？

编辑：我添加了XAML部分和添加方法。

这是绑定ObservableCollection的XAML代码。

<Border Grid.Row="6" Grid.ColumnSpan="3" Height="100">
   <ItemsControl x:Name="ListKeywords" ItemsSource="{Binding SearchKeywords, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}">
      <ItemsControl.ItemsPanel>
         <ItemsPanelTemplate>
            <WrapPanel />
         </ItemsPanelTemplate>
      </ItemsControl.ItemsPanel>
      <ItemsControl.ItemTemplate>
         <DataTemplate>
            <local:CrossLabel MyLabel="{Binding}" Remove="Kw_Remove"/>
         </DataTemplate>
      </ItemsControl.ItemTemplate>
   </ItemsControl>
</Border>

这是Methode

private void Kw_Add(object sender, RoutedEventArgs e)
{
    if (!_families.SearchKeywords.Contains(this.Keywords.Text))
    {
        _families.SearchKeywords.Add(this.Keywords.Text);
    }
}

当我将关键字添加到＆＃34; _families.SearchKeywords＆＃34; ItemControle获取新项目，但过滤器威望与ViewModel不适用。

Answer 1

只需在构造函数中订阅CollectionChanged事件，无需每次都替换该集合。

public ViewModel()
{
    searchKeywords.CollectionChanged += searchKeywords_CollectionChanged;
}

void searchKeywords_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
    throw new NotImplementedException();
}

Answer 2

将项目添加到ObservableCollection会导致集合触发其CollectionChanged事件。这与OnPropertyChanged无关。您的SearchKeywords属性属于ViewModel类的属性 - 只有在您实际更改OnPropertyChanged的值时才会调用SearchKeywords方法，即替换ObservableCollection 1}}使用完全不同的ObservableCollection。

将项添加到ObservableCollection <string>时更新ViewModel并传递过滤器

2 个答案: