Setting up data structure for bindings

[Lawrence]

I am lost on how to setup the treelistview with regard to lazy loading hierarchial collections.  As an example I would like the treelistview("TLV") to be bound to a collection of PhotoAlbums in the viewmodel.  Each PhotoAlbum has a Collection<Photo> Photos property, and each Photo has a Collection<Tag> property.  I would like to use the TLV to represent this in a hierarchial manner.  I am unclear on how to set this up using the ChildTableDefinitions.  Moreover, the RowLoaded event does not pass a row that has a clear mechanism of displaying the expander control similar to the treeview  and allowing you to catch the expanded event to load the data (similar to TreeView AllowLazyLoading).  I only saw a single readonly property for HasHierarchy. 

I understand the TLV is not "officially released" so I wasnt able to find any docs on it, however if you could offer a sample app of how to use it in the above scenario, I know it would likely benefit many other besides myself and further encourage adoption.

[Vlad]

Hello Lawrence,

 The easiest way will be to implement this at your model level - directly in these properties getters. You can check this blog post (related to RadGridView) for more info about such approach.

Best wishes,
Vlad
the Telerik team

[Lawrence]

So that article indicates how I might implement lazy loading, but how do I set up the hierarchial structure to work with the TLV?  What I have below does not seem to work:

<telerik:RadTreeListView
            infra:BindingViewModel.BindingObject="{Binding}"
            x:Name="RadTreeListView1"
            AutoGenerateColumns="False"
            IsReadOnly="True"
            DataLoadMode="Asynchronous"
            ItemsSource={Binding PhotoAlbums}
            SelectedItem="{Binding SelectedItem, Mode=TwoWay}"
            IsSynchronizedWithCurrentItem="true">
            <telerik:RadTreeListView.ChildTableDefinitions>
                <telerik:TreeListViewTableDefinition />
                <telerik:TreeListViewTableDefinition
                    ItemsSource="{Binding Photos}">
                    <telerik:TreeListViewTableDefinition.ChildTableDefinitions>
                        <telerik:TreeListViewTableDefinition
                            ItemsSource="{Binding Tags}" />
                    </telerik:TreeListViewTableDefinition.ChildTableDefinitions>
                </telerik:TreeListViewTableDefinition>
            </telerik:RadTreeListView.ChildTableDefinitions>
            <telerik:RadTreeListView.Columns>
                <telerik:GridViewDataColumn
                    MinWidth="200"
                    DataMemberBinding="{Binding}"
                    Header="Name"
                    CellTemplateSelector="{StaticResource ItemTemplateSelector}"/>
                <telerik:GridViewDataColumn
                    MinWidth="100"
                    DataMemberBinding="{Binding CreatedDate}"
                    Header="CreatedDate" />
            </telerik:RadTreeListView.Columns>
        </telerik:RadTreeListView>-->

[Vlad]

Hello Lawrence,

I've just noticed that you have heterogeneous data in your case. Generally RadTreeListView can be used to display homogeneous data (all hierarchy levels will have same columns/properties) - in case of heterogeneous you can use RadGridView.

Best wishes,
Vlad
the Telerik team