Last Updated: 05 Feb 2024 15:48 by Martin Ivanov

By default the TextSearchPath of RadAutoCompleteBox is automatically assigned when the DisplayMemberPath is set, and if the TextSearchPath is not yet assigned. However, this happens only initially. Runtime changes of the DisplayMemberPath don't update the text search path.

To work this around, set the TextSearchPath manually when you change the DisplayMemberPath.

Last Updated: 11 Sep 2023 10:25 by ADMIN
Release LIB 2023.2.918 (18 Sep 2023)
NullReferenceException in AppendModeBase.SetTextForHighlightedItem when the value of DisplayMemberPath is null.
Last Updated: 23 May 2023 11:28 by ADMIN
Release R2 2023
Created by: Martin Ivanov
Comments: 0
Category: AutoCompleteBox
Type: Bug Report
The performance during text search filtering was noticeably decreased in scenario with big amount of data (100k+ items). This is related to the TypeConverter support introduced in the filtering.
Last Updated: 06 Jun 2022 07:56 by ADMIN
Created by: Mateusz
Comments: 1
Category: AutoCompleteBox
Type: Bug Report

When using Windows 11 theme with 4.5 NoXaml binaries, AutoCompleteBox reports a XAML Binding Failure:

To reproduce, just run the following window (just an empty AutoCompleteBox) in a new WPF Framework project:

<Window x:Class="WpfApp20.MainWindow"
        xmlns:local="clr-namespace:WpfApp20" xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        Title="MainWindow" Height="450" Width="800">
                <ResourceDictionary Source="/Telerik.Windows.Themes.Windows11;component/Themes/System.Windows.xaml"/>
                <ResourceDictionary Source="/Telerik.Windows.Themes.Windows11;component/Themes/Telerik.Windows.Controls.xaml"/>
                <ResourceDictionary Source="/Telerik.Windows.Themes.Windows11;component/Themes/Telerik.Windows.Controls.Input.xaml"/>

Last Updated: 31 May 2022 08:35 by ADMIN
Release LIB 2022.2.606 (06 June 2022)

I've encountered a tiny bug when it comes to styling AutoCompleteBox using StyleManager.
If I set the StyleManager.ApplicationTheme of my app, the styling is correct, see the reference gif:

But if I set the style of AutoCompleteBox during runtime with StyleManager.SetTheme, the styling is not quite right - the underlying RadWatermarkBox is using the basic style I believe, because the text doesn't change it opacity when I hover over it (in the case of watermark text) or when I defocus the element (in the case of real text).

The example I'm using is just an empty WPF project with MainWindow.xaml having one RadAutoCompleteBox inside it, and MainWindow.xaml.cs is pictured in the gifs.


Best Regards,

Last Updated: 18 Feb 2022 11:24 by ADMIN
Release R1 2022 SP1


unfortunately, I have yet another bug report regarding the RadAutoCompleteBox. This time, it looks like a regression introduced in one of the last two Releases of Ui for WPF as we recently upgraded from 2021.3.914.45 to 2022.1.117.45 and the crash only happens with the newer version.

In one of our applications we get an InvalidOperationException: "Cannot modify the logical children for this node at this time because a tree walk is in progress."  when setting RadPane.Hidden = true for a Pane that contains at least one RadAutoCompleteBox.

In the attached text file you can find the full stack trace. I noticed that RadPaneGroup inherits from RadTabControl so maybe the regression was caused by some of the changes in my other report regarding AutoCompleteBoxes in TabControls. The pattern seems to be the same at least: The crash only seems to occur if you type into the AutoCompleteBox and select an item from the DropDown.

Crash occurs if:

  • You type into the box, select an item from the Dropdown and then switch to another module (see attached gif).

Crash does not occur if:

  • The AutoCompleteBox is not touched at all
  • The bound properties are only changed by the ViewModel
  • You type into the box to trigger the Dropdown but do NOT select an item


As a side note:

While debugging the issue I noticed that RadNavigationView seems to have an exception handler somewhere that silently swallows this exception, causing really strange behavior in the RadDocking control. I also attached a gif for this behavior (-UI.gif).

 	Telerik.Windows.Controls.Navigation.dll!Telerik.Windows.Controls.RadNavigationView.OnSelectionChangerSelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e = {System.Windows.Controls.SelectionChangedEventArgs})	Unknown
 	Telerik.Windows.Controls.dll!Telerik.Windows.Controls.SelectionChanger<System.__Canon>.InvokeSelectionChangedEvent(System.Windows.Controls.SelectionChangedEventArgs e)	Unknown
 	Telerik.Windows.Controls.dll!Telerik.Windows.Controls.SelectionChanger<System.__Canon>.End()	Unknown
 	Telerik.Windows.Controls.dll!Telerik.Windows.Controls.SelectionChanger<object>.AddJustThis(object item)	Unknown
>	Telerik.Windows.Controls.Navigation.dll!Telerik.Windows.Controls.RadNavigationView.UpdateSelection(System.Windows.Controls.Primitives.Selector targetSelector, object item)	Unknown
 	Telerik.Windows.Controls.Navigation.dll!Telerik.Windows.Controls.RadNavigationView.NotifyNavigationViewItemClick(Telerik.Windows.Controls.RadNavigationViewItem container)	Unknown
 	Telerik.Windows.Controls.Navigation.dll!Telerik.Windows.Controls.RadNavigationViewItem.OnClickInternal()	Unknown
 	Telerik.Windows.Controls.Navigation.dll!Telerik.Windows.Controls.RadNavigationViewItem.OnClick()	Unknown
 	PresentationFramework.dll!System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(System.Windows.Input.MouseButtonEventArgs e)	Unknown

Simon Müller
Hofmann Fördertechnik GmbH


Last Updated: 07 Feb 2022 09:46 by ADMIN
Release LIB 2022.1.207 (7 Feb 2022)
Created by: Simon
Comments: 8
Category: AutoCompleteBox
Type: Bug Report


while integrating a RadAutoCompleteBox into our application, I noticed a problem when binding to its SearchText and SelectedItem properties:

How we use the AutoCompleteBox:
We use the following XAML markup to create the AutoCompleteBox:

<telerik:RadAutoCompleteBox Grid.Column="0" x:Name="UnitSelectionAutoCompleteBox"
IsEnabled="{Binding UnitNumberEnabled, Mode=OneWay}"
ItemsSource="{Binding UnitSelectionComponent.SearchResults, Mode=OneWay}"
SearchText="{Binding UnitSelectionComponent.UnitNumberSearchText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
SelectedItem="{Binding UnitSelectionComponent.SelectedUnit, Mode=TwoWay}"
WatermarkContent="{StaticResource Loc.UnitNumber}">
All of the bound properties use the INotifyPropertyChanged interface to communicate changes to the ui - there is no code behind, behavior or anything else modifying the properties. We bind to the SearchText in order to dynamically load matching items into the available items list since we are searching through a database table with >100.000 entries.

The problem

Having bound both, the SelectedItem and the SearchText leads to the SearchText binding to break under some circumstances: If UnitSelectionComponent.SelectedUnit is not null when the UI is loaded initially, the SearchText property suddenly contains a hard-coded string instead of the binding we defined. However, there seems to be another required condition I don't know yet since I was not able to reproduce the problem in a simple demo project.


I attached three screenshots of our ui and Snoop:

- binding_working shows the control and its SearchText binding in the default state.

- binding_working2 shows the control and its SearchText binding after selecting an item by first typing into the AutoCompleteBox and then selecting an item from the dropdown.

- binding_broken shows the control and its SearchText binding in the broken state: Instead of the binding, SearchText now only contains a string.


What I found out so far:

- The issue occurs in two cases:

    1. If I open the module with a preselected item (e.g. by opening a saved document),

    2. If I use a separate selection module to select an item (the selection module is displayed by temprarily switching the DataContext to show the selection UI. When a new item is selected, we set the SelectedUnit and then the DataContext is switched back to show the module ui again, see RadAutoCompleteBox_LostBinding.gif)

- If the SelectedItem is not bound, the issue does not seem to occur.

- Forcing the ui to be reloaded (e.g. by switching to a different module and then back) makes the binding come back.


Simon Müller
Hofmann Fördertechnik GmbH


Won't Fix
Last Updated: 20 Dec 2021 15:51 by Stenly
When clicking the remove button on an item, which is present more than once in the selection textbox, the first occurrence will be removed, rather than the corresponding item.
Last Updated: 29 Nov 2021 11:30 by ADMIN
Release LIB 2021.3.1129 (29 Nov 2021)
When selecting an item from the drop-down menu, scrollviewer's position is not changed when the menu is opened again.
Last Updated: 04 Oct 2018 09:48 by ADMIN
The workaround is to set String.Empty for TextSearchPath before setting the new value for the DisplayMemberPath
Last Updated: 20 Jul 2018 07:30 by ADMIN
Last Updated: 13 Apr 2018 07:22 by ADMIN
Created by: Dilyan Traykov
Comments: 0
Category: AutoCompleteBox
Type: Bug Report
The current workaround is to directly set the value of the underlying TextBox instead:

this.RadAutoCompleteBox.ChildrenOfType<TextBox>().First().Text = "1 I";
Last Updated: 07 Nov 2017 08:33 by ADMIN
When you start typing, the dropdown appears and then you leave the AutoCompleteBox without clicking, the cursor is not changing back to arrow.

As a workaround of the issue you could manually release the mouse capture in the Populated event handler of the control as shown below:

 private void AutoCompleteBox_Populated(object sender, System.EventArgs e)
            if (Mouse.Captured is RadAutoCompleteBox)
                (sender as RadAutoCompleteBox).ReleaseMouseCapture();
Last Updated: 09 Mar 2017 15:08 by ADMIN
If you have RadAutoCompleteBox above RadPanelBarItems and the expanded drop down menu (of the RadAutoCompleteBox) covers them, if you click over some of the drop down items the RadPanelBarItem below gets clicked too.
The fix is available in  Q2 2013 Release.
Last Updated: 15 Feb 2017 08:42 by ADMIN
Available in LIB version 2017.1.213 , it will be also available in the R1 2017 SP1 Release.
Last Updated: 03 Jan 2017 21:20 by ADMIN
Last Updated: 09 Dec 2016 07:42 by ADMIN
Clicking the ScrollViewer of the control causes the focus to be retained by the RadAutoCompleteBox, leading to double mouse click required in order to access outside control.

Also the mouse cursor is changed IBeam value rather than the default Arrow value.

The fix is available in the 2016 R3 SP1 release.
Last Updated: 17 Oct 2016 15:04 by ADMIN
Available in LIB version 2016.3.1017, it will be also available in the 2016 R3 SP1 release. 
Last Updated: 17 Oct 2016 14:58 by ADMIN
When the SelectedItems property is bound, moving items inside that collection causes ArgumentException.

Available in LIB version 2016.3.1017, it will be also available in the 2016 R3 SP1 release. 
Last Updated: 17 Oct 2016 14:56 by ADMIN
On start up a Binding error is thrown in the Output for ElementName=WatermarkTextBox.

Available in LIB version 2016.3.1017, it will be also available in the 2016 R3 SP1 release. 
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