Questions on UI for WPF Forum

0 answers

10 views

WebCam Preview Very Jerky With Logitech C920e

This can be duplicated in the Telerik UI for WPF Desktop Examples app.

One of my clients uses a fleet of Logitech C920e cameras to capture photos. The RadWebCam's preview is very jerky and severely lags behind camera movement on every kind of computer we've tested (all running Windows 11) . This issue isn't present with the couple other camera models we've tested.

I've tested other webcam photo capture apps on Windows 11 and they all work fine with this camera (no lags, no jerkiness). This includes DevExpress's "Outlook-Inspired Application" demo WPF app.

WebCam

asked on 01 Sep 2025

2 answers

19 views

ScheduleView file-based saving/loading

I'm looking to load/save the appointments to a local file rather than a database.

I found a forum post from 2015 which seems a bit out of date.

Is there any facility for this and if not what is the suggested route? I don't want to ship a database source within my application.

Many thanks

ScheduleView

answered on 25 Aug 2025

0 answers

14 views

Filtering bug

There appears to be a bug in the column filter popup. Whenever I change one filter operator, the second filter operator changes to the same value. So I can't do something like GreaterThan X and LessThan Y.

See a video here: https://share.cleanshot.com/6Bn9FwlJ

GridView

asked on 20 Aug 2025

1 answer

12 views

PDFViewer use ContextMenu with DocumentSource Binding

Hi,

I have this code, thats not working like this.

Because of the DataContext, the DocumentSource wont work, because it needs obviously a different DataContext.
But I need this DataContext for the ContextMenu to work.

Is there a way I can have both? A working context menu and also bind the DocumentSource?

Greetings
Benedikt

        <telerik:RadPdfViewerToolBar 
            Grid.Row="1"
            x:Name="pdfViewerToolBarZeichnungen" 
            Margin="0 5 0 0"
            RadPdfViewer="{Binding ElementName=pdfViewerZeichnungen}" 
            HasSaveButton="{DynamicResource SonderRechtPDFsSpeichernErlaubt}" 
            HasSignatureButton="False" 
            HasPercentComboBox="False" 
            HasPrintButton="{DynamicResource SonderRechtPDFsSpeichernErlaubt}" 
            />
        <telerik:RadPdfViewer 
            Grid.Row="2" 
            x:Name="pdfViewerZeichnungen" 
            DocumentSource="{Binding SelDatei.FilePath, Converter={StaticResource PdfDocumentSourceValueConverter}}"
            DataContext="{Binding CommandDescriptors, ElementName=pdfViewerZeichnungen}" 
            telerik:RadPdfViewerAttachedComponents.RegisterFindDialog="True" 
            telerik:RadPdfViewerAttachedComponents.RegisterContextMenu="True"
            Mode="TextSelection"
            >

PDFViewer

answered on 18 Aug 2025

1 answer

16 views

RadListBox Drop Line Sizing Issue with DragVisualProvider

Hello!

I'm trying to use DragVisualProvider on my ListBox:

            <telerik:RadListBox.DragDropBehavior>
                <telerik:ListBoxDragDropBehavior AllowReorder="False"/>
            </telerik:RadListBox.DragDropBehavior>

            <telerik:RadListBox.DragVisualProvider>
                <telerik:ScreenshotDragVisualProvider />
            </telerik:RadListBox.DragVisualProvider>          

            <telerik:RadListBox.ItemsPanel>
                <ItemsPanelTemplate>
                    <telerik:RadWrapPanel HorizontalAlignment="Stretch"/>
                </ItemsPanelTemplate>
            </telerik:RadListBox.ItemsPanel>

However, the "drop line" (the blue vertical line that indicates where the item will be dropped) is not sizing correctly. It appears to be much larger than the items themselves, as you can see in the attached image.

How can I fix this so that the drop line fits the size of the other images? Am I missing a property or a specific configuration?

Any help would be greatly appreciated. Thanks!

ListBox

answered on 13 Aug 2025

1 answer

21 views

RadRichTextBox loosing image positions

I use RadRichTextBox (WPF) to edit HTML documents.

These contain images with annotations.

It works as expected (except for the context menu popping up when I mark an image) and I can position the images according to my needs.

See Before.png where the red arrow points to something in the image.

When I save the HTML and load it into the RadRichTextBox again the image positioning is totally gone. See After.png

Am I missing something or does the HtmlDataProvider simply not work as expected?

RichTextBox

answered on 08 Aug 2025

1 answer

19 views

Bug: NullReferenceException raised by IGridViewEditor.SetText in DateTimePickerGridViewEditor when typing a key into a GridViewDataColumn that contains a collapsed RadDateTimePicker

Is this the best place to report bugs?

This is with 2024.4.1213.462.

To duplicate the issue:

With VS 2022, create a WPF (.NET Framework) application,
Delete MainWindow.xaml and MainWindow.xaml.cs
Unzip the attached file, place MainWindow.xaml and MainWindow.xaml.cs from the zip where the old files were or use the pasted text below
Build and run the application
Put focus on a cell in a row in the grid and type a letter

Expect the following exception to be raised

	Name	Value	Type
◢	$exception	{"Object reference not set to an instance of an object."}	System.NullReferenceException

at Telerik.Windows.Controls.DateTimePickerGridViewEditor.Telerik.Windows.Controls.GridView.IGridViewEditor.SetText(String text) in Telerik.Windows.Controls\DateTimePickerGridViewEditor.cs:line 56

In case the zip doesn't work:

MainWindow.xaml.cs:

namespace WpfApp14
{
    using System;
    using System.ComponentModel;
    using System.Windows;
    using System.Collections.ObjectModel;

    public sealed class GridValueViewModel : INotifyPropertyChanged
    {
        private string someValue = string.Empty;

        public GridValueViewModel(string someValue)
        {
            this.SomeValue = someValue;
        }

        public event PropertyChangedEventHandler PropertyChanged;

        public string SomeValue
        {
            get
            {
                return this.someValue;
            }

            set
            {
                value = value ?? string.Empty;
                if (this.SomeValue != value)
                {
                    this.someValue = value;
                    this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(this.SomeValue)));
                }
            }
        }

        public DateTime? DateValue
        {
            get
            {
                if (DateTime.TryParse(this.SomeValue, out var value))
                {
                    return value;
                }

                return null;
            }

            set
            {
                if (value == null)
                {
                    this.SomeValue = string.Empty;
                    return;
                }

                this.SomeValue = value.ToString();
            }
        }

        public ObservableCollection<string> SomeValueItems { get; } = new ObservableCollection<string>(
            new[]
            {
                "cat",
                "dog",
                "bird"
            });
        
    }

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            this.InitializeComponent();
            this.DataContext = this;
        }

        public ObservableCollection<GridValueViewModel> Values { get; } = new ObservableCollection<GridValueViewModel>(
            new[]
            {
                new GridValueViewModel("cat"),
                new GridValueViewModel("dog"),
                new GridValueViewModel("bird")
            });
    }
}

MainWindow.xaml:

<Window x:Class="WpfApp14.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <telerik:RadGridView
        AutoGenerateColumns="False"
        ItemsSource="{Binding Values, Mode=OneWay}">
        <telerik:RadGridView.Columns>
            <telerik:GridViewDataColumn
                Header="Column 1">
                <telerik:GridViewDataColumn.CellTemplate>
                    <DataTemplate>
                        <Label
                            Content="{Binding SomeValue}" />
                    </DataTemplate>
                </telerik:GridViewDataColumn.CellTemplate>
                <telerik:GridViewDataColumn.CellEditTemplate>
                    <DataTemplate>
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition
                                    Width="*" />
                            </Grid.ColumnDefinitions>
                            <TextBox
                                Grid.Column="0"
                                Text="{Binding SomeValue, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}"
                                Visibility="Collapsed" />
                            <telerik:RadComboBox
                                Grid.Column="0"
                                HorizontalAlignment="Stretch"
                                IsEditable="False"
                                ItemsSource="{Binding SomeValueItems}"
                                SelectedItem="{Binding SomeValue}" />
                            <telerik:RadDateTimePicker
                                Grid.Column="0"
                                HorizontalAlignment="Stretch"
                                InputMode="DatePicker"
                                DateTimeWatermarkContent="{x:Null}"
                                SelectedValue="{Binding DateValue, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}"
                                Visibility="Collapsed" />
                        </Grid>
                    </DataTemplate>
                </telerik:GridViewDataColumn.CellEditTemplate>
            </telerik:GridViewDataColumn>
        </telerik:RadGridView.Columns>
    </telerik:RadGridView>
</Window>

DateTimePicker

GridView

answered on 07 Aug 2025

0 answers

11 views

Filter on CalculatedItem

Hello,

is there a possibility to create a Value Filter or some sort of filtering on a CalculatedItem (https://docs.telerik.com/devtools/wpf/controls/radpivotgrid/features/localdatasourceprovider/local-calc-items)?

Best

Simon

PivotGrid

asked on 01 Aug 2025

1 answer

23 views

Add a custom palette with its own name in a Telerik RadColorPicker

Hello, I want to add a custom palette with its own names and colors in WPF. But seems like I can only work with built-in MainPalette, HeaderPalette, AdditionalContent

The image below shows my intention. I want to add not only 2 of them, but as many as I want.

ColorPicker

answered on 29 Jul 2025

1 answer

17 views

EditMask With DateTimePicker

Is there a way to use RadMaskedDateTimeInput with RadDateTimePicker? Users want to be able dates in MM/dd/yyyy format (without typing the slashes) or use the calendar picker. I believe RadDateTimePicker uses RadWatermarkTextBox which does not have tight input control.

DateTimePicker

answered on 29 Jul 2025