用于WPF DataGrid的CollectionViewSource MVVM实现

I have implemented small demo of CollectionViewSource for WPF DataGrid in MVVM. I would really appreciate any help to verify the implementation and comment on whether this is the right approach to use CollectionViewSource.

我在MVVM中为WPF DataGrid实现了CollectionViewSource的小型演示。我真的很感激任何帮助来验证实现并评论这是否是使用CollectionViewSource的正确方法。

public class ViewModel : NotifyProperyChangedBase
{       
    private ObservableCollection<Movie> _movieList;
    public ObservableCollection<Movie> MovieList
    {
        get { return _movieList; }
        set
        {
            if (this.CheckPropertyChanged<ObservableCollection<Movie>>("MovieList", ref _movieList, ref value))
                this.DisplayNameChanged();
        }
    }

    private CollectionView _movieView;
    public CollectionView MovieView
    {
        get { return _movieView; }
        set
        {
            if (this.CheckPropertyChanged<CollectionView>("MovieView", ref _movieView, ref value))
                this.DisplayNameChanged();
        }
    }

    public ViewModel()
    {
          MovieView = GetMovieCollectionView(MovieList);
    }

    private void DisplayNameChanged()
    {
        this.FirePropertyChanged("DisplayName");
    }

    public void UpdateDataGrid(string uri)
    {            
        MovieView = GetMovieCollectionView(new ObservableCollection<Movie>(MovieList.Where(mov => uri.Contains(mov.ID.ToString())).ToList<Movie>()));
    }

    public CollectionView GetMovieCollectionView(ObservableCollection<Movie> movList)
    {
        return (CollectionView)CollectionViewSource.GetDefaultView(movList);
    }

The XAML View :

XAML视图：

  <Window.Resources>
     <CollectionViewSource x:Key="MovieCollection" Source="{Binding MovieList}">
    </CollectionViewSource>
  </Window.Resources>
   <DataGrid Name="MyDG" 
             ItemsSource="{Binding MovieView}" 
             AutoGenerateColumns="True" />

The Code Behind :

守则背后：

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        this.Resources.Add("TagVM", new TagViewModel());
        this.DataContext = this.Resources["TagVM"];
    }

    private void Hyperlink_Click(object sender, RoutedEventArgs e)
    {
        string uri = ((Hyperlink)sender).NavigateUri.ToString();
        ((ViewModel)this.DataContext).UpdateDataGrid(uri);
    }

The Hyperlink_Click handler invokes the UpdateDataGrid method of the VM passing it comma seperated movie IDs which are then used to filter the MovieList collection using extension methods.

Hyperlink_Click处理程序调用VM的UpdateDataGrid方法，传递它的逗号分隔的电影ID，然后使用扩展方法过滤MovieList集合。

3 个解决方案

#1

You should not create new instances of the observable collection and the collection view. Assign a predicate to the filter property on the collecion view and call Refresh whenever you want to filter the collection.

您不应该创建可观察集合和集合视图的新实例。将谓词分配给集合视图上的filter属性，并在需要过滤集合时调用Refresh。

public class ViewModel : NotifyProperyChangedBase
{       
    string uri;

    public ObservableCollection<Movie> MovieList { get; private set; }

    public CollectionView MovieView { get; private set; }

    public ViewModel(MoveList movieList)
    {
        MovieList = movieList;
        MovieView = GetMovieCollectionView(MovieList);
        MovieView.Filter = OnFilterMovie;
    }

    public void UpdateDataGrid(string uri)
    {     
        this.uri = uri;
        MovieView.Refresh();
    }

    bool OnFilterMovie(object item)
    {
        var movie = (Movie)item;
        return uri.Contains(movie.ID.ToString());
    }

    public CollectionView GetMovieCollectionView(ObservableCollection<Movie> movList)
    {
        return (CollectionView)CollectionViewSource.GetDefaultView(movList);
    }
}

#2

Here is an example of instantiating a CollectionViewSource in order to enable multi-filtering in a DataGrid: http://www.codeproject.com/Articles/442498/Multi-filtered-WPF-DataGrid-with-MVVM

下面是一个实例化CollectionViewSource以在DataGrid中启用多重过滤的示例：http：//www.codeproject.com/Articles/442498/Multi-filtered-WPFurdayGrid-with-MVVM

The CollectionViewSource was instantiated in the XAML view but is bound to a collection of objects instantiated in the view model. The view model then uses the CollectionViewSource to filter the data in the DataGrid.

CollectionViewSource在XAML视图中实例化，但绑定到视图模型中实例化的对象集合。然后，视图模型使用CollectionViewSource过滤DataGrid中的数据。

As to what is the right approach to instantiate a CollectionViewSource - that is debatable.

至于什么是实例化CollectionViewSource的正确方法 - 这是有争议的。

#3

You can skip adding resources by doing this directly : DataContext = new TagViewModel(); and doing your bindings normally. but I highly recommend using Dependency Injection.

您可以通过直接执行此操作来跳过添加资源：DataContext = new TagViewModel（）;并正常做你的绑定。但我强烈建议使用依赖注入。

#1