Gridview doesn't update when the bound data changes

Question

I've bound my data grid and a bunch of check boxes to the following properties in my view model (typed Presenter).

public ListCollectionView AllOrdersView { get; set; }

public IEnumerable<CarrierType> AllCarrierTypes
{
  get { return _allCarrierTypes; }
  set
  {
    _allCarrierTypes = value;
    OnPropertyChanged();
  }
}

In the constructor of it, I assign a filter like so.

public Presenter()
{
  _allOrders = new ObservableCollection<Order>(DataAccessor.GetOrders());
  AllOrdersView = new ListCollectionView(_allOrders);
  AllOrdersView.Filter = element => AllCarrierTypes
    .Where(x => x.Active).Contains(((Order)element).CarrierType);
}

The aim is to filter off the orders that have a carrier of type that's unchecked. At the moment, it seems that the filtration only takes place initially, as the constructor is invoked. My hope was that, since the check boxes are bound, I need no further intervention with the code. It's not the case. As I select/deselect the check boxes, the data grid stays unaffected.

Furthermore, suspecting that it's got to do with the need to refresh the view, I added a call to the view as follows.

private void ToggleButton_OnUnchecked(Object sender, RoutedEventArgs eventArgs)
{
  ((Presenter)DataContext).AllOrdersView.Refresh();
}

Sadly, that doesn't seem to make any difference and I'm all stuck. So, my questions are these.

Do I need to refresh explicitly in the event handler at all?
Do I need to add another (kind of) binding?
Do I need to implement anything more in the view model?

My bindings are done in the following way.

<ListBox ItemsSource="{Binding AllCarrierTypes}">
  <ListBox.ItemTemplate>
    <DataTemplate>
      <CheckBox Content="{Binding Name}"
                IsChecked="{Binding Active,Mode=TwoWay}"
                Checked="ToggleButton_OnChecked"
                Unchecked="ToggleButton_OnUnchecked"/>
    </DataTemplate>
  </ListBox.ItemTemplate>
</ListBox>

<DataGrid x:Name="dataGrid" 
          ItemsSource="{Binding AllOrdersView}"
          AutoGeneratingColumn="DataGrid_OnAutoGeneratingColumn" .../>

Edit

Per requestion - full version of the CarrierType class in the model.

public class CarrierType : INotifyPropertyChanged
{
  private bool _active;

  public int Id { get; set; }
  public String Name { get; set; }
  public bool Active
  {
    get { return _active; }
    set
    {
      _active = value;
      OnPropertyChanged();
    }
  }

  public override String ToString()
  {
    return Name;
  }

  public event PropertyChangedEventHandler PropertyChanged;

  [NotifyPropertyChangedInvocator]
  protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
  {
    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
  }
}

eran otzap · Accepted Answer · 2015-01-18 16:31:18Z

1

There's seems to be a problem with the ListCollectionView in .NET 4.5 (not sure if the problem existed earlier). You would need to call Refresh() but it doesn't seem to work.

What I do is to re-assign the filter.

private void ToggleButton_OnUnchecked(Object sender, RoutedEventArgs eventArgs)
{
  AllOrdersView.Filter = element => AllCarrierTypes
    .Where(x => x.Active).Contains(((Order)element).CarrierType); 
}

As requested in the comments below :

  <CheckBox IsChecked="{Binding Active,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"/>

edited Jan 18, 2015 at 16:31

answered Jan 17, 2015 at 19:35

eran otzap

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12 Comments

Konrad Viltersten Over a year ago

Do you have a link to some kind of documentation of it? Are there any others way to work-around it? Is there any chance that it's intended behavior and that we just misuse it? Also, I notice that you omitted the part referring to the view model instance through DataContext. Is that possible? I always go through that, cast and then refer to it, which is inconvenient.

eran otzap Over a year ago

MSDN : "Re-creates the view. "

eran otzap Over a year ago

I just crossed paths with this issue multiple times , i would love to find out i'm mistaken .

Konrad Viltersten Over a year ago

You might actually be onto something, so +1. When I set the filter to null in my event handler, I get the difference in the data set shown. However, it seems not to follow the selection of the check boxes. Suggestions?

eran otzap Over a year ago

Yes that's a different question . Checked and Unchecked are different events in WPF CheckBox

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