Last Updated: 25 Jun 2024 11:41 by Benjamin
Calculated values are not updated when updating other values in the grid.
Last Updated: 03 Jun 2024 13:31 by Petar
SelectedItems collection not updated when items are removed
Last Updated: 28 May 2024 08:17 by ADMIN

We use a RadTreeView with many different item types that set a DefaultImageSrc based on a combination of item type and state
(from each item's view model).

For the currently selected TreeView item we would like to modify the item's image with a coloured border.
So it would be a very useful feature, if the TreeView item's SelectedImage could be derived from the DefaultImageSrc
via XAML Shapes (Rectangle, Line, etc.).
(Shapes can e.g. already be used to draw TreeView's Expander-Button for expanded/collapsed state, which is very useful).

Currently the only approach is to copy any item-type's image in the file system and modify it for selected state.
(Thus doubling the number of item image files.)
Given the number of images for different item types and states that we already have, this is not very practical.

Examples for DefaultImageSrc (left) and SelectedImageSrc (right):

  •  -> 
  •  -> 

Is it possible to extend RadTreeView, so that the SelectedImageSrc can be based on the given DefaultImageSrc, but with a modification provided via XAML?

Last Updated: 26 Jan 2024 10:57 by Kostiantyn
RadTreeViewItemEditedEventArgs returns the same object in the OldValue and NewValue properties when using the Edited event.
Last Updated: 23 May 2023 12:04 by ADMIN
Release R2 2023
Change the selection on MouseLeftButtonUp instead of MouseLeftButtonDown.
Last Updated: 27 Apr 2023 16:18 by Stenly

The items of the RadTreeView control do not behave correctly in a touch scenario when expanding/collapsing them.

A possible workaround for this behavior would be to set the TouchManager.ShouldSuspendMousePromotion attached property to True on the RadTreeView control instance.

Last Updated: 14 Feb 2023 08:41 by ADMIN
Release R1 2023
The example modifies the DropPosition of the dragged item to Inside on drag over. This could lead to an exception in the default drag-drop logic if the dragged item and the drop target are of the same type. This exception causes the dragged item to disappear when it is dropped.
Last Updated: 16 Dec 2022 08:58 by ADMIN
RadTreeView with virtualization turned on, defines HierarchicalDataTemplates for its items. 

In the template, the root panel is 32 pixels (or higher than the default TreeViewItemHeight - 24 px in OfficeBlackTheme). Scrolling the treeview, then maximizing the wpf window results in misplaced / incorrect height of treeviewitems.

Possible workaround:
Set the MinHeight property of RadTreeViewItem so that all its header content fits. Then set the item's VerticalContentAlignment to Stretch
        <Style TargetType="telerik:RadTreeViewItem">
                         <Setter Property="MinHeight" Value="48" />
                        <Setter Property="VerticalContentAlignment" Value="Stretch" />

Also following settings might help:
- setting fixed width/height of the RadTreeView
- setting ChildDefaultLength to 48 of every TreeviewPanel:
					<telerik:TreeViewPanel ChildDefaultLength="48" />
        <Style x:Key="ItemContainerStyle" TargetType="{x:Type telerik:RadTreeViewItem}">
			<Setter Property="ItemsPanel">
						<telerik:TreeViewPanel ChildDefaultLength="48" />
Last Updated: 31 May 2022 14:26 by ADMIN
Release LIB 2022.2.606 (6 Jun 2022)
Setting custom ItemContainerStyleSelector is sometimes not applied to every item of the RadTreeView control, when the TreeVirtualizationMode is set to Hierarchical.
Last Updated: 17 May 2022 09:39 by ADMIN
Setting the color variation of the VisualStudio2019Palette to ColorVariation.Dark of the VisualStudio2019 theme makes the TreeViewItem elements difficult to read (gray foreground on a white background).
Last Updated: 28 Feb 2022 15:03 by ADMIN
Release LIB 2022.1.307 (7 March 2022)

TreeView is in dropdowncontent of a DropDownButton. BringPathIntoView is called on loaded of the button (or the tree). It tries to bring several nested levels deep for example item (4 levels deep).
On opening the button , the scrollviewer is not scrolled to the desired item.

Posssible workarounds:

 - invoke the BringPathIntoView method in a Dispatcher.BeginInvoke call

 - disable the treeview animations before the call and enable them after the call ( telerik:AnimationManager.IsAnimationEnabled = False)

Last Updated: 31 May 2021 08:03 by ADMIN
Release LIB 2020.2.504 (05/04/2020)
Selection is not updated when using the arrow keys if the current selected item is outside the viewport.
Last Updated: 07 Apr 2021 05:41 by ADMIN
Release LIB 2021.1.412 (12/04/2021)

Select an item with mouse, scroll thousands of items down and then shift select item to perform range selection. This will block the UI thread for seconds. 

Last Updated: 05 Apr 2021 10:29 by ADMIN
Created by: Markus
Comments: 1
Category: TreeView
Type: Bug Report

Dear Telerik team,
We currently have a problem with the RadDragAndDropManager as we are currently in the process of converting from Silverlight to WPF.
We are also converting Telerik from version 2011.2 to the current version of Telerik WPF.
Now the following error happens:
If I drag an item and drag it over another dropable area, the DragCue element moves.
The error occurs as soon as "e.QueryResult" is set to true in the OnDropQuery function.
You just have to do that, otherwise the drop will not be evaluated.

I was able to recreate the whole thing in a new project with just a RadTreeView and a RadMap.
I just don't want to switch the RadDragAndDropManager to the DragDropManager because we have a lot of our own controls that run with the old one, but not with the new one.
I've already tried that, but the conversion effort is just too big.
Can you see why the DragCue element is acting so weird?

With best regards

Markus Kuhlemann

Last Updated: 08 Feb 2021 11:40 by ADMIN
Release LIB 2021.1.208 (2/8/2021)
Last Updated: 24 Aug 2020 10:56 by ADMIN
Release LIB 2020.2.824
The children of an expanded RadTreeViewItem dropped inside another item are not indented correctly. 
Last Updated: 26 May 2020 08:34 by ADMIN
Release LIB 2020.2.525 (5/26/2020)

Select nested item in virtualized treeview with single selection mode.

Collapse its parent. Select item in the level of the parent. Expand the parent and notice two items are visually selected.

Expexted : only the last selected item with mouse should be visually selected.


private void TreeView_ItemPrepared(object sender, RadTreeViewItemPreparedEventArgs e)
    if ((e.PreparedItem.IsSelected == true && this.TreeView.SelectedItem != null && this.TreeView.SelectedItem != e.PreparedItem.Item))
        e.PreparedItem.IsSelected = false;
Last Updated: 08 Apr 2020 06:59 by ADMIN


I found a bug when drag&dropping selected tree nodes (extended multi-selection) when the tree is virtualized. Items that never got into view are missing from the Payload Manager Data object. If virtualization is off, works as expected.

Please see modified sample for demonstration. I added 200+ items to League A -> Division A. Select the first item, quickly scroll by dragging vertical scrollbar to the bottom of the list and extend selection to the whole list. Then perform drag and drop. Note, not all items were moved.

Also, the drag visual helper moves and updates very very slowly when dragging hundredths of objects. In our application, we have thousands of objects, which makes it unusable


Thank you for a quick fix.


Last Updated: 20 Feb 2020 13:40 by ADMIN
Release R1 2020 SP
Virtualized TreeView is bound to collection of models and IsSelected of RadTreeViewItem is 2way bound to IsSelected of model.
Select the 10th item with mouse. 
Reset the items of the tree to a subset (1-15) containing the selected item.
Select the 5th item with mouse and shift key down.
Expected: Range 5-10 of items is selected.
Actual: Range 10-15 of items is selected.

Last Updated: 18 Feb 2020 08:28 by ADMIN
Release R1 2020 SP
When switching to a different window, the selected item in the RadTreeView stays in a selected in-focus state. The expected behavior is not to be focused any more (turn gray).
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