Starting with the upcoming Q2 2026 release, the following themes will no longer be supported for newly introduced controls:

• Expression Dark
• Windows 7
• Transparent
• Vista
• Summer
• Office Silver
• Office Blue

Note: This change applies only to newly introduced controls. Support for all of the existing ones (available before Q2 2026) that already use these themes will remain unchanged, and they will continue to function as before.

19 Jan to 26 Jan 2026: highlights of the new online resources that we published last week.

Article: https://www.telerik.com/products/wpf/documentation/controls/radbuttons/commands
Summary: Learn how to use WPF commanding with Telerik UI for WPF RadButtons: bind ICommand to RadButtonBase (RadButton, RadToggleButton, RadSplitButton), set CommandParameter and CommandTarget, and rely on CanExecute/CanExecuteChanged to control enabled state. You’ll see MVVM-friendly patterns for routed and custom commands and when each control invokes Command, so you can replace Click handlers and centralize execution logic.

Article: https://www.telerik.com/products/wpf/documentation/controls/radchat/message-status
Summary: This article shows how to display and update message delivery state in the WPF RadChat control, covering common states like Sending, Sent, Delivered, Read, and Failed via each message’s Status property and the built-in enum. It demonstrates updating the status from your async/MVVM workflow and customizing the status indicator (visibility, placement, and visuals) using styles, DataTemplates, or a template selector.

Article: https://www.telerik.com/products/wpf/documentation/controls/radbuttons/popup-animation
Summary: Configure the drop-down popup animation for Telerik UI for WPF RadButtons, specifically RadDropDownButton and RadSplitButton. The article shows how to enable or disable open/close animations and adjust settings like duration and easing in XAML, with options to apply them per control or across the application for consistent behavior and performance.

Article: https://www.telerik.com/products/wpf/documentation/controls/radbuttons/button-extensions
Summary: This article shows you how to use the Telerik WPF ButtonExtensions attached properties to extend ButtonBase-derived controls (such as RadButton and related buttons) with additional behavior and visuals without retemplating. It enumerates the available extensions, explains their effects and default values, notes which controls they apply to, and provides examples for configuring them in XAML in an MVVM-friendly way.

Article: https://www.telerik.com/products/wpf/documentation/controls/radbuttons/features/speech-to-text-button
Summary: Add a Speech-to-Text Button from RadButtons to your WPF app to start/stop microphone dictation and insert recognized text into a target TextBox or other input at the caret. Configure the target element and recognition culture, and handle listening, result, and error events to control the flow; the control uses the machine’s speech recognition engine and requires microphone access.

Article: https://www.telerik.com/products/wpf/documentation/controls/radpdfviewer/customization-and-extensibility/custom-ui-layer
Summary: This article shows you how to add a custom UI layer to the WPF RadPdfViewer to render overlays (e.g., highlights, adorners, interactive elements) above PDF pages without modifying the document. You implement and register a layer in the viewer’s UI layer pipeline so it stays synchronized with zoom and scrolling, position elements using document-to-view/page transforms, and control z-order, hit testing, and updates on layout/viewport changes.

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15 Dec to 22 Dec 2025: highlights of the new online resources that we published last week.

Article: https://www.telerik.com/products/wpf/documentation/knowledge-base/kb-pdfviewer-filenotfoundexeception-systemfontsmanager
Summary: This article explains why RadPdfViewer for WPF can throw a FileNotFoundException referencing SystemFontsManager at runtime and how to resolve it. It covers common root causes—missing or mismatched Telerik.Windows.Documents.* assemblies, PublishTrimmed/single-file publish removing types, or assemblies not copied to output—and provides fixes: reference the correct Telerik.Windows.Documents.Core/Fixed versions, ensure Copy Local, and either disable trimming or explicitly preserve the Telerik.Documents types so SystemFontsManager and related font support are included in the deployment.

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10 Nov to 17 Nov 2025: highlights of the new online resources that we published last week.

Summary: Learn how to use RadPdfViewer’s Find feature in WPF to search text in PDF documents, navigate next/previous matches, and highlight results. The article explains the built-in Find UI, commands and API for initiating searches, configuring options like match case and whole word, and handling events to react to search state changes, with code examples for integrating the search UI and driving it from code-behind or MVVM.

Article: https://www.telerik.com/products/wpf/documentation/controls/radpdfviewer/save-as
Summary: Use RadPdfViewer for WPF’s Save As to export the currently loaded PDF to a new file, preserving edits such as annotations and form fields. Invoke it from the UI or programmatically with RadPdfViewerCommands.SaveAs targeting your RadPdfViewer instance. The command is available regardless of whether the document was opened from a file path or a stream.

Article: https://www.telerik.com/products/wpf/documentation/controls/radpdfviewer/printing
Summary: Learn how to print PDFs from RadPdfViewer in a WPF application using the built-in Print command or programmatically from code-behind. The article shows how to invoke the WPF PrintDialog and configure print settings (for example, scaling and other output options) to control the printed result.

Article: https://www.telerik.com/products/wpf/documentation/controls/radpdfviewer/bookmarks
Summary: Learn how to enable and use the Bookmarks pane in RadPdfViewer for WPF to display a PDF’s hierarchical outline and navigate to bookmark destinations. The article shows how to toggle the pane in the built-in UI and how to access and traverse bookmarks programmatically so you can implement custom navigation or integrate bookmarks into your own controls.

Article: https://www.telerik.com/products/wpf/documentation/controls/radpdfviewer/scrolling
Summary: This article explains how to configure and control scrolling in RadPdfViewer for WPF, including vertical/horizontal scrollbars, continuous document scrolling, and how zoom and fit modes affect the viewport. It details user interactions (mouse wheel, touch, keyboard) and shows how to scroll programmatically to a page or offset and handle scroll changes through the viewer’s API.

Article: https://www.telerik.com/products/wpf/documentation/ai-assistant/mcp-server-as-a-nuget
Summary: This guide shows you how to install and self-host an MCP (Model Context Protocol) server via a NuGet package in a WPF app and connect it to RadAIAssistant. You will configure the server and register tools/resources so an LLM can invoke application capabilities through MCP.

Article: https://www.telerik.com/products/wpf/documentation/controls/radpdfviewer/ai-summarization
Summary: Learn how to enable AI summarization in the WPF RadPdfViewer so you can summarize the entire PDF or the current selection via built-in summarize commands. You configure an LLM provider, connect it to the viewer, invoke the commands, and optionally customize prompt text and output (length/format), with guidance on async execution, context/token limits, and error handling.

Article: https://www.telerik.com/products/wpf/documentation/controls/radpdfviewer/digital-signature
Summary: This article shows how to view and validate PDF digital signatures in RadPdfViewer for WPF, including displaying signature widgets, inspecting signer/certificate details, and reporting validity (trusted, expired, revoked, or document modified). It explains how to configure validation by providing trusted root certificates and enabling revocation checks (OCSP/CRL), handle user interactions with signatures, and notes that creating signature fields or signing PDFs is done with PdfProcessing.

Article: https://www.telerik.com/products/wpf/documentation/controls/radpdfviewer/interactive-forms
Summary: RadPdfViewer for WPF supports interactive PDF AcroForm forms, allowing you to display and fill fields such as text boxes, check boxes, radio buttons, list/combo boxes, and push buttons directly in the viewer. You can read and write field values, control focus and keyboard navigation, and handle standard form actions (submit/reset) through the API; XFA forms are not supported.

Article: https://www.telerik.com/products/wpf/documentation/controls/radpdfviewer/export-fixedpage-to-image
Summary: Learn how to export a WPF RadPdfViewer page (FixedPage) to an image (PNG/JPEG) by retrieving the FixedPage for a given PDF page, converting it to a bitmap, and saving it to a file or stream with control over size and DPI/scale. The article explains handling page virtualization and layout so you can export pages that aren’t currently visible and generate consistent thumbnails and previews from C# code.

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29 Oct to 05 Nov 2025: highlights of the new online resources that we published last week.

Summary: This article shows you how to use Telerik UI for WPF in .NET Core/.NET SDK-style WPF projects, outlining supported target frameworks and the Windows-only scope. You add the Telerik packages from your private NuGet feed, reference the controls and XAML namespaces, merge theme resource dictionaries, and account for Visual Studio design-time support and differences from .NET Framework.

Article: https://www.telerik.com/products/wpf/documentation/security/overview
Summary: This article outlines the Telerik UI for WPF security model: assemblies are strong-named and Authenticode-signed, and the controls are designed for full-trust desktop applications rather than partial-trust environments (e.g., XBAP or partial-trust ClickOnce). It provides guidance to reduce risk—avoid loading untrusted XAML or documents, gate clipboard/drag-and-drop/printing/file access, keep dependencies updated, and align your app with .NET/WPF security practices.

Feel free to check them out and share your thoughts!

The Telerik Team

As of 2024 Q4 (November), we will deprecate the .NET 7 distribution. This decision is rooted in our dedication to align with Microsoft’s recommended framework versions so that our products leverage the latest advancements in technology, security, and performance.  

We are aligning our product with Microsoft’s lowest-supported framework versions for .NET Framework and .NET, respectively. Please refer to the following blog post: Product Update for Enhanced Performance and Security

For more information about how to upgrade your project when a new version of the Telerik UI for WPF suite is released, you can check here: Project Migration to .NET 4.6.2 and .NET 6

As of 2024 Q2, we will deprecate .NET Framework 4.0, .NET Framework 4.5, and .NET Core 3.1 distributions. This decision is rooted in our dedication to align with Microsoft’s recommended framework versions so that our products leverage the latest advancements in technology, security, and performance.

We are aligning our product with Microsoft’s lowest-supported framework versions for .NET Framework and .NET, respectively. Please refer to the following blog post:

Product Update for Enhanced Performance and Security (telerik.com)

For more information about how to upgrade your project's .NET Framework version, you can check the following MSDN article:

Migration Guide to .NET Framework 4.8, 4.7, and 4.6.2 - .NET Framework | Microsoft Learn

Hi ,

We have integrated RadRichTextBox into our WPF (C#) application and are trying to add RadCallout as a custom context menu. since the control is being created entirely in code-behind without XAML ,we are encountering implementation challenges.

Could you please guide us on how to achieve this?

Hello,

I have attempted to implement the solutions listed here.

We are using various ColorVariations along with our themes, however. For example:

StyleManager.ApplicationTheme = new Windows11Theme(Windows11Palette.ColorVariation.Dark);

The solutions listed in the link above throw the following exception:

System.InvalidOperationException: The calling thread cannot access this object because a different thread owns it.

Is there a way to use theme ColorVariations along with RadSplashScreen?

Thank you

We have an app that has RadComboBox controls arranged above some RadNumericUpDown controls. For the RadNumericUpDown controls we have it set up to open a numeric pad on PreviewMouseUp to support both mouse and touch. The issue we have is that when a combobox item is selected that lies over a numericupdown using touch, the numericupdown control receives the focus and activates the numeric pad. This does not occur when using a mouse.

Attached is an example derived from our app that reproduces this behavior. Selecting Pounds or Newtons from the Force combobox using touch will cause a message box to appear.

Is there any way to work around this behavior? It is annoying but not a show-stopper.

Thanks,
Jim

Hi,

When using RadGridView ExportAndShow method (GridViewExportFormat = Csv or Txt), the first data row is inserted next to column headers, it's missing a carriage return.

ResultGrid.ExportAndShow(GridViewExportFormat.Csv, "fileName.txt", true);

I'm using Telerik.UI.for.Wpf.80.Xaml 2025.4.1321

We are encountering severe UI thread blocking when using RadOpenFolderDialog during high-volume file operations (concurrent exports).

Technical Findings: After investigating the internal implementation, we identified the root cause in the DialogWindowBase class. Specifically, inside the SetupDialogContent method, the AddWatcher parameter is hardcoded to true.

This forces the underlying DirectoryInfoWrapper to initialize a FileSystemWatcher and unconditionally subscribe to the following events:

• Changed
• Created
• Deleted
• Renamed

Because our application generates a large volume of file events during export, these subscriptions flood the message pump and hang the UI thread.

The Question: Since AddWatcher is hardcoded, is there a supported way (or a workaround via reflection/subclassing) to:

Override SetupDialogContent to pass AddWatcher = false?

Access the DirectoryInfoWrapper instance post-initialization to manually unsubscribe from these events?

We urgently need to stop this component from listening to file system changes to maintain application responsiveness.

Version: 2024.4.1213.462