Working With Bindable SelectedItems Collection in RadTreeView

[Stacey Haslag]

I am using the RadTreeView control for the first time. I am using the MVVM approach to interact with this control. What I want to do is be able to set and get the SelectedItems of the RadTreeView. I am allowing multiple selections to occur. I have the initial heirarchy list of business objects that I bind to the control. But I can't find a way to neatly interact with a collection of the selected items.

I have read a lot of the various instructions in this area http://www.telerik.com/help/silverlight/radtreeview-how-to-bind-hierarchical-data-use-containerbindingcollection.html. They lead me to using the ContainerBindingCollection and HierarchicalDataTemplate approach. So I have done this, and this is binding my collection of datasource business objects appropriately. 

However, this still does not get me exactly what I want. Maybe it is not possible, but what I would like is a way to bind to the SelectedItem property, and receive a collection of selected items; and vice-verca to Set the SelectedItem list, and have the appropriate items selected.

With the way that it is set up using the ContainerBindingCollection approach, I don't see a way to do that...would I have to build my own collection of selected items one-by-one as they select them?

Here is my XAML:

<telerik:ContainerBindingCollection x:Name="BindingsCollection">

            <telerik:ContainerBinding PropertyName="IsSelected" Binding="{Binding IsSelected, Mode=TwoWay}"></telerik:ContainerBinding>

        </telerik:ContainerBindingCollection>



<telerik:RadTreeView Margin="0, 20, 0, 20" SelectionMode="{Binding SelectionMode}" ItemsSource="{Binding SortedTableOfContentsList}"

                             SelectedItem="{Binding SelectedPage, Mode=TwoWay}">

            <telerik:RadTreeView.ItemTemplate>

                <telerik:HierarchicalDataTemplate ItemsSource="{Binding RelatedPages}" 

                                                  telerik:ContainerBinding.ContainerBindings="{StaticResource BindingsCollection}">

                    <StackPanel Orientation="Vertical" VerticalAlignment="Bottom">

                        <TextBlock Text="{Binding Description}"></TextBlock>

                        <TextBlock FontSize="9" Text="{Binding Notes}" Margin="10, 0, 0, 0"></TextBlock>

                    </StackPanel>

                </telerik:HierarchicalDataTemplate>

            </telerik:RadTreeView.ItemTemplate>

        </telerik:RadTreeView>

Notes: I do get all my heirarchy items to show in my tree list appropriately. I do have an "IsSelected" property added to my business object for binding. I am getting my "SelectedPage" property to fire in my view model for each item that is selected...it just fires one at a time as items are selected individually.

Thanks!
Stacey

[Petar Mladenov]

Hi Stacey Haslag,

First I would like to note that in Extended selection mode, the SelectedItem is always the first item in the SelectedItems collection: SelectedItems[0]. However, could you please examine this blog post showing a possible way to synchronize the SelectedItems colelction with a collection of business items in the ViewModel.
Please let us know if this approach fits in your scenario.

Kind regards,
Petar Mladenov
the Telerik team

[Stacey Haslag]

Sorry for the late response to this! Yes, this scenario does fit my situation; I am now able to interact with the SelectedItems collection. Thanks for your help!

Stacey