There is no way to prevent that behavior, other than expanding the TreeView again. You can read about expanding TreeView in the following 3 posts: part 1, part 2, part 3.

Bea

In relation to an earlier post, if a Property changes and we do cvs.View.Refresh(), it collapses the entire tree and we need to expand it to see the changes. Is there any way to prevent this ?

Templating anonymously typed data works fine, as long as you give the template a key in the resources, and point the ItemTemplate to that key. Implicit templates (the ones that are applied by setting the DataType property) will not work in this scenario.

I created a simple sample of a ListBox bound to a collection of anonymous types, and used an explicit DataTemplate to template the data items. You can find it here. You can do something similar for TreeView, by setting the ItemTemplate property of the TreeView, plus the ItemTemplate property of the HierarchicalDataTemplate.

Let me know if this helps.

Bea

Is there a way to use Hierarchical datatemplate on the treeview with anonymous types?
I want to bind treeview to a result of LINQ query without wrapping it in a concrete type.

Thanx, Alex

I updated this sample to work with Orcas Beta 2 bits. You can find the new project here.

Thanks,
Bea

Currently, if you change the property you’re grouping on, we don’t refresh the groups automatically. You can refresh them yourself with the following code:

CollectionViewSource cvs = this.Resources["cvs"] as CollectionViewSource;
cvs.View.Refresh();

We discussed the feature you’re asking a long time ago, but decided to not add it in the first version of WPF because it’s not trivial to design. For your particular scenario, since you’re using PropertyGroupDescription to generate the groups, it would be easy for grouping code to listen to property changes on the property specified. However, if the user decides to use custom grouping, we would not be able to rely on INotifyPropertyChanged to get change notifications. We want to support this feature at some point, but that will require either only support non-custom grouping, or coming up with a new design that supports all kinds of groupings.

You can see a project with this blog sample working with property changes here.

Thanks,
Bea

I’m using INotifyPropertyChanged but it doesnt’ seem to ‘move’ my frog over into the next group.

You can add another level of grouping by adding a second PropertyGroupDescription to the GroupDescriptions collection of CollectionViewSource. Does this answer your question?

Thanks,
Bea