This is a bug report. I think I may have come across a problem in the RadTreeListView control while navigating the cells using the keyboard arrow keys.
Problem Context (may not be relevant): RadTreeListView with several columns, column 0 being a hierarchy column. The control's ItemSource is bound to an EntitySet<T> containing a self-referencing hierarchy, so T has a property called Children, made up of further T's:
<telerik:RadTreeListView.ChildTableDefinitions>
<telerik:TreeListViewTableDefinition ItemsSource="{Binding Children}" />
</telerik:RadTreeListView.ChildTableDefinitions>
The XAML header for my RadTreeListView is:
<telerik:RadTreeListView x:Name="RBSTreeListView1"
AutoGenerateColumns="False"
CanUserFreezeColumns="False"
GridLinesVisibility="Both"
RowIndicatorVisibility="Collapsed"
HorizontalAlignment="Left"
VerticalAlignment="Bottom"
Height="Auto"
MaxHeight="700"
EnableRowVirtualization="True"
ScrollViewer.HorizontalScrollBarVisibility="Auto"
ScrollViewer.VerticalScrollBarVisibility="Auto"
HierarchyExpandButtonStyle="{StaticResource st}"
HierarchyColumnIndex="0"
SelectionUnit="Cell"
SelectionMode="Extended"
>
With SelectionMode="Extended" attribute present, and moving the cell selection around with the arrow keys, I experience the following unhandled exception when navigating from one of the hierarchy leaf nodes on the left side of the control (in column 0), back to a grid cell (in column 1) of the same row:
Code 4004
Category: ManagedRuntimeError
Message: 'System.ArgumentNullException: Value cannot be null.'
Parameter name: key
When I remove the SelectionMode="Extended" XAML attribute, I no longer experience this unhandled exception.
(Point #2... a related side note: When SelectionMode is not specified and while navigating around the control's grid with the keyboard, any attempt to move from a hierarchy leaf node cell to a regular (non-hierarchy) cell to its right is blocked. The same is not true if a rightwards move occurs from a hierarchy node that has children. Why is this so?)