在 WPF MVVM 中使用 ICollectionView 更新 DataGrid

Question

I have rather interesting problem. I have a DataGrid in wpf that looks like:

<DataGrid ItemsSource="{Binding View, IsAsync=True, Mode = TwoWay}"
          AutoGenerateColumns="False" 
          EnableColumnVirtualization="True" 
          EnableRowVirtualization="True"
          VirtualizingStackPanel.VirtualizationMode="Standard"
          VirtualizingStackPanel.IsVirtualizing="True">
     COLUMNS
</DataGrid>

On data in that grid I am performing crud operations, but it seems I cannot refresh view after Add or Delete operation, it works perfectly when I Update record or filter it.

Simple C# ops I tried in view model.

Read:

    public CommendationViewModel()
    {
        this._catalog = new CatalogContexct();
        this._commendations = this._catalog.Commendations.ToList();

        var commendation = new ListCollectionView(this._commendations);
        this.CommendationView = CollectionViewSource.GetDefaultView(commendation);

        this.AddCommand = new RelyCommand(AddEntity, param => this._canExecute);
        this.EditCommand = new RelyCommand(EditEntity, param => this._canExecute);
        this.UpdateCommand = new RelyCommand(UpdateEntity, param => this._canExecute);
        this.RemoveCommand = new RelyCommand(RemoveEntity, param => this._canExecute);

        this.NameCommand = new RelyCommand(Filter, param => this._canExecute);
        this.CancelCommand = new RelyCommand(Cancel, param => this._canExecute);
    }

And add:

    public void AddEntity(object obj)
    {
        if(string.IsNullOrEmpty(this.Name))
        {
            MessageBox.Show("Brak nazwy do dodania");
            return;
        }
        var commendation = new Commendation() { Name = this.Name };
        this._catalog.Commendations.Add(commendation);
        this._catalog.SaveChanges();

        var commendationRefresh = new ListCollectionView(this._catalog.Commendations.ToList());
        this.CommendationView = CollectionViewSource.GetDefaultView(commendationRefresh);
        this.CommendationView.Refresh();            

        MessageBox.Show("Nowe źródło polecenia zostało dodane");
    }

As you see I tried to Refresh view in add command but it did not work. Any suggestions?

Answer 1

Bind to CommendationView:

<DataGrid ItemsSource="{Binding CommendationView}" ...

...and make sure that the setter of this property raises the PropertyChanged event:

private ICollectionView _commendationView;
public ICollectionView CommendationView
{
    get { return _commendationView; }
    set { _commendationView = value; NotifyPropertyChanged(); }
}

The view model class must implement the INotifyPropertyChanged interface for this to work: https://msdn.microsoft.com/en-us/library/system.componentmodel.inotifypropertychanged(v=vs.110).aspx