当项目被添加时,Observablecollection不更新列表

Question

我正在使用MVVM模式,并希望使用可观察的集合更新ListView.我经历了几个SO问题,但看不出我做错了什么.任何帮助深表感谢.谢谢.

View.xaml

命名空间: xmlns:local="clr-namespace:MusicPlayer.ViewModel"

DataContext的

<UserControl.DataContext>
    <local:AllTracksViewModel/>
</UserControl.DataContext>

列表显示

<ListView x:Name="TrackListView" 
                  ItemsSource="{Binding Path=TrackListObservable}">
...
<ListView.View>
   <GridView>
     <GridViewColumn Header="Title" Width="250" DisplayMemberBinding="{Binding Title}" />
      <GridViewColumn Header="Album" Width="200" DisplayMemberBinding="{Binding Album}" />
      <GridViewColumn Header="Artist" Width="150" DisplayMemberBinding="{Binding Artist}" />
      <GridViewColumn Header="Duration" Width="100" DisplayMemberBinding="{Binding FormattedDuration}" />
      </GridView>
    </ListView.View>
</ListView>

ViewModel.cs

public class AllTracksViewModel
{
    public ObservableCollection<Track> TrackListObservable { get; private set; }

    public AllTracksViewModel()
    {
        TrackListObservable = new ObservableCollection<Track>();
    }
}

我确认项目肯定会被添加到observable中.再一次感谢你的帮助.

Answer 1

将您的代码更改为:

public class AllTracksViewModel : INotifyPropertyChanged
{
    ObservableCollection<Track> trackListObservable;

    public event PropertyChangedEventHandler PropertyChanged;

    public ObservableCollection<Track> TrackListObservable {
      get { return trackListObservable; }
      set {
        trackListObservable = value;
        if(PropertyChanged!=null) {
          PropertyChanged(this, new PropertyChangedEventArgs("TrackListObservable"));
        }
      }
}

    public AllTracksViewModel()
    {
        TrackListObservable = new ObservableCollection<Track>();
    }
}

只是为了解释原因:ViewModel的每个属性都应该通知它的更改.