16 Mar to 23 Mar 2026: highlights of the new online resources that we published last week.

Article: https://www.telerik.com/products/winforms/documentation/knowledge-base/scheduler-print-24-hour-format
Summary: This article shows how to print RadScheduler (Telerik UI for WinForms) with 24-hour time (HH:mm) instead of the default 12-hour/AM/PM format. It demonstrates configuring the printing pipeline by customizing the scheduler print style to format time labels with a 24-hour pattern, or by applying a culture that uses 24-hour time, and provides the code to apply these changes before print or print preview.

Article: https://www.telerik.com/products/winforms/documentation/knowledge-base/dock-custom-context-menu-documentwindow
Summary: Learn how to replace the default context menu for RadDock DocumentWindow in Telerik UI for WinForms with your own RadContextMenu. You intercept right-clicks on document tabs/windows, suppress the built-in menu, resolve the clicked DocumentWindow, and show a custom menu wired to actions like Close, Close All, or your own commands.

Article: https://www.telerik.com/products/winforms/documentation/knowledge-base/richtexteditor-align-table-cell-content
Summary: This article shows how to align table cell content in Telerik UI for WinForms RadRichTextEditor using the document model API: set Paragraph.TextAlignment for horizontal text alignment and TableCell.VerticalAlignment for vertical alignment. It provides C# examples for iterating cells (from the current selection or an entire table) and applying these settings programmatically.

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09 Mar to 16 Mar 2026: highlights of the new online resources that we published last week.

Article: https://www.telerik.com/products/winforms/documentation/knowledge-base/syntaxeditor-collapse-expand-nodes
Summary: Learn how to programmatically collapse and expand code folding (outlining) regions in RadSyntaxEditor for WinForms using C#. You’ll access the editor’s folding/outlining tagger to toggle specific regions by span or line and implement Collapse All / Expand All so the editor UI updates correctly.

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09 Feb to 16 Feb 2026: highlights of the new online resources that we published last week.

Article: https://www.telerik.com/products/winforms/documentation/controls/speechtotextbutton/events
Summary: This page details the SpeechToTextButton events in Telerik UI for WinForms and when they fire throughout the speech recognition lifecycle (listening started/stopped, partial/interim results, final result, and errors). Use these events to subscribe handlers that capture transcripts, inspect event args for text, confidence, and exceptions, and update your UI and logic as the button toggles between idle and recording.

Article: https://www.telerik.com/products/winforms/documentation/controls/speechtotextbutton/states
Summary: This article explains the visual and functional states of the WinForms SpeechToTextButton (e.g., Idle, Listening, Processing, Disabled) and how each state affects the button’s appearance and behavior. You learn how to start/stop listening, query and change the current state programmatically, and handle state-change events to update your UI. It also outlines where to customize state indicators and styles through theming.

Article: https://www.telerik.com/products/winforms/documentation/controls/speechtotextbutton/overview
Summary: Learn how to use the RadSpeechToTextButton control in Telerik UI for WinForms to start/stop speech recognition from a microphone and insert transcribed text into a target input control (such as a text box). The article shows how to add the control, configure the target control and recognition settings (e.g., culture/grammars), and handle recognition lifecycle and error events, plus prerequisites like an available microphone and enabled Windows speech recognition.

Article: https://www.telerik.com/products/winforms/documentation/controls/speechtotextbutton/appearance
Summary: This article shows you how to style the SpeechToTextButton control in Telerik UI for WinForms: apply built-in themes (via ThemeName or ThemeResolutionService) and customize the visual tree with Visual Style Builder. You’ll adjust text/image layout (e.g., TextImageRelation and ImageAlignment), replace the microphone icons for different states, and tweak colors, borders, and fonts, including how to override theme values when setting appearance at runtime.

Article: https://www.telerik.com/products/winforms/documentation/controls/map/features/transparency-tiles
Summary: This article explains how RadMap for WinForms renders transparent map tiles (PNG alpha) and how to use them to build hybrid maps by layering a transparent tiles source (e.g., labels/roads) over a base imagery provider. It shows how to configure layer order and background to make transparency useful and outlines considerations when mixing tile providers that return transparent tiles.

Article: https://www.telerik.com/products/winforms/documentation/controls/speechtotextbutton/getting-started
Summary: Learn how to add and configure the SpeechToTextButton (RadSpeechToTextButton) in Telerik UI for WinForms to capture microphone input and populate a text control. You’ll add the control via the Designer or code, set the target text box, choose the recognition language/culture and input device, start/stop recognition, and handle recognition and error events to process results reliably.

Article: https://www.telerik.com/products/winforms/documentation/controls/speechtotextbutton/custom-recognizer
Summary: This article shows how to integrate a custom speech recognition engine with the WinForms SpeechToTextButton by implementing the control’s recognizer interface and wiring your implementation to the button. It outlines the required contract (start/stop/cancel operations, partial and final result events, state changes, and error reporting) and demonstrates attaching your recognizer so the button controls recognition, updates its state, and outputs recognized text using services like Azure, Google, Amazon, or on‑prem engines.

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

Article: https://www.telerik.com/products/winforms/documentation/knowledge-base/gridview-tracking-visible-rows
Summary: Learn how to detect which data rows are currently visible in RadGridView for WinForms, taking virtualization, scrolling, filtering, and grouping into account. The article shows two approaches: compute the visible range using the table element’s RowScroller (vertical scrollbar value and viewport size), and enumerate the currently realized GridDataRowElement instances to access their RowInfo/DataBoundItem, with examples wired to scroll and resize events.

Article: https://www.telerik.com/products/winforms/documentation/knowledge-base/gridview-export-groups-collapsed
Summary: Learn how to export a grouped WinForms RadGridView to Excel (XLSX) with all groups collapsed on open using GridViewSpreadExport. You handle the exporter’s WorkbookCreated callback and set each worksheet RowGroup to collapsed (e.g., iterate Worksheet.RowGroups and set IsCollapsed = true) so the resulting file preserves the collapsed state of the grid’s groups. Note: this behavior relies on SpreadExport (XLSX); the older ExcelML exporter cannot persist collapsed outline groups.

Article: https://www.telerik.com/products/winforms/documentation/knowledge-base/listview-custom-item-arrangeoverride
Summary: This article shows you how to create a custom RadListView visual item in Telerik UI for WinForms and precisely control its layout by overriding ArrangeOverride (and MeasureOverride). You’ll subclass SimpleListViewVisualItem/BaseListViewVisualItem, add child LightVisualElement elements (e.g., image and text) in CreateChildElements, compute and assign bounds in ArrangeOverride, and plug your item in via the VisualItemCreating event to achieve custom item layouts.

Article: https://www.telerik.com/products/winforms/documentation/knowledge-base/autocompletebox-remove-duplicate-text
Summary: This article shows how to remove duplicate text in Telerik UI for WinForms RadAutoCompleteBox by preventing duplicate tokens and sanitizing pasted, delimiter-separated input. You validate each new entry against the existing Tokens collection (case-insensitive) and either cancel the duplicate or rebuild the text from unique values to keep the control’s content deduplicated.

Article: https://www.telerik.com/products/winforms/documentation/knowledge-base/datetimepicker-custom-freeform-parser
Summary: Learn how to add a custom free‑form date/time parser to Telerik WinForms RadDateTimePicker so users can type dates in multiple formats (e.g., 1/2, 2024-01-02, 2pm) and still produce a valid Value. You’ll intercept the editor’s TextChanging/ValueChanging flow, parse with DateTime.TryParse/TryParseExact using defined patterns and CultureInfo, cancel the default parsing, set the normalized DateTime, and surface validation when parsing fails.

Article: https://www.telerik.com/products/winforms/documentation/knowledge-base/diagram-enable-autoscroll-dragging-shape
Summary: Enable auto-scroll in Telerik UI for WinForms RadDiagram while you drag a shape, so the canvas pans when the pointer nears the control edges. You’ll handle the drag operation to detect edge proximity and programmatically scroll the viewport (via the control’s scrollbars), with adjustable edge thresholds and scroll step to tune speed and responsiveness.

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05 Jan to 12 Jan 2026: highlights of the new online resources that we published last week.

Article: https://www.telerik.com/products/winforms/documentation/introduction
Summary: This introduction explains what Telerik UI for WinForms includes and which .NET/Windows targets it supports, covering theming, high DPI, localization, RTL, accessibility, and touch. Use it to install the controls from the Telerik NuGet feed or the installer, set up Visual Studio design-time, and navigate to getting started, API reference, and guides for core controls like RadGridView, ChartView, Scheduler, Ribbon, Dock, PDF Viewer, and RichTextEditor, plus theming and upgrade guidance.

Article: https://www.telerik.com/products/winforms/documentation/security/faq
Summary: This Security FAQ explains how Telerik UI for WinForms handles key security topics: assembly/code signing, third‑party dependencies and CVE monitoring, telemetry/data collection, network behavior, and operation under restricted permissions (including FIPS or locked‑down environments). It also details the vulnerability reporting and patching process and provides guidance to help you securely use, configure, and update the controls in your WinForms applications.

Article: https://www.telerik.com/products/winforms/documentation/core/overview
Summary: This overview explains how to use Telerik UI for WinForms with .NET Core and .NET 5/6/7/8 on Windows, including supported runtimes, Visual Studio and Windows Forms Designer requirements, and toolbox integration. You’ll learn how to create or migrate SDK-style WinForms projects, reference the correct .NET-targeted assemblies via NuGet or local binaries, and handle build/deploy specifics, with notes on platform limitations and known issues.

Article: https://www.telerik.com/products/winforms/documentation/knowledge-base
Summary: Use the Telerik UI for WinForms Knowledge Base to find troubleshooting guides, how-to articles, and code examples for common control scenarios such as GridView, data binding, theming, printing, and performance. Search and filter the articles to quickly locate task-focused solutions you can apply directly in your project to fix issues or implement features. Each entry summarizes the problem context and provides the steps or code needed to resolve it.

Article: https://www.telerik.com/products/winforms/documentation/core/design-time
Summary: This article explains design-time support for Telerik UI for WinForms when targeting .NET Core and .NET 5/6/7 in the Visual Studio Windows Forms Designer. You’ll verify prerequisites, install/reference the Telerik assemblies via NuGet, integrate controls into the Toolbox, and use designer features like smart tags, themes, and the Property Grid. It also outlines known limitations of the .NET Core designer and provides troubleshooting guidance.

Article: https://www.telerik.com/products/winforms/documentation/security/overview
Summary: This article explains how to secure applications built with Telerik UI for WinForms and what you are responsible for: ship official strong‑named assemblies, keep the suite updated, run with least privilege, and treat all data bound to controls as untrusted. It outlines best practices for controls that load files or markup (document viewers/editors), including validating and sanitizing input, restricting or disabling external resource loading and hyperlink actions, and avoiding deserialization of untrusted content, and it points you to the product’s vulnerability reporting and support policies.

Article: https://www.telerik.com/products/winforms/documentation/tools/themeviewer
Summary: This article explains how to use the ThemeViewer to preview and validate Telerik UI for WinForms themes across the control suite. You load built-in or custom themes (including ones created with Visual Style Builder), switch between controls and states, and test scenarios like DPI scaling and RightToLeft to catch visual issues before integrating a theme into your application.

Article: https://www.telerik.com/products/winforms/documentation/core/core-migration
Summary: This guide shows you how to migrate a Telerik UI for WinForms app from .NET Framework to .NET (Core/.NET 5+), either by converting the existing project to SDK-style or by creating a new .NET WinForms project and moving your code. You’ll retarget the TFM and replace assembly references with the Telerik .NET packages from the Telerik NuGet feed, then rebuild. It also covers resource/settings handling (resx, app.config via System.Configuration.ConfigurationManager), WinForms designer requirements in Visual Studio, publishing, and common fixes such as adding Microsoft.Windows.Compatibility, resolving missing APIs, licensing considerations, and 32/64-bit differences.

Article: https://www.telerik.com/products/winforms/documentation/controls/clock/clock
Summary: Use RadClock (Telerik UI for WinForms) to show an analog clock and optionally let users pick a time; this article shows how to add the control in the designer or code, set the time via the Value (DateTime) property, and handle ValueChanged. It also details appearance and behavior settings, theming, and embedding RadClock in RadTimePicker.

Article: https://www.telerik.com/products/winforms/documentation/controls/chat/toolbar
Summary: This article shows you how to configure the RadChat toolbar in Telerik UI for WinForms: enable/disable the toolbar, add and arrange toolbar items, and control their visibility. You’ll create toolbar items, handle click events, and customize icons, tooltips, and layout to add actions (for example, attachments or emoji) next to the chat input.

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

Summary: This article explains how to add the Telerik UI for WinForms license key in an add-in project (e.g., VSTO/COM) to avoid runtime licensing errors. It shows where to register the key during add-in startup and how to embed the license file as an Embedded Resource so the license is applied before any Telerik controls are instantiated.

Article: https://docs.telerik.com/devtools/winforms/controls/pdfviewer/features/ai-summarization
Summary: RadPdfViewer for WinForms supports AI summarization of PDF content, allowing you to generate summaries for the entire document or the currently selected text. You configure an OpenAI or Azure OpenAI provider (API key and model), enable the built-in summarization UI/commands, and customize prompt templates to control the output for your use case.

Article: https://docs.telerik.com/devtools/winforms/knowledge-base/calendar-add-custom-space-footer
Summary: Learn how to add a custom footer area to RadCalendar in Telerik UI for WinForms by extending the control and injecting a LightVisualElement into its element tree to reserve space at the bottom. The article shows how to set a fixed height, align the footer, and update layout so the footer persists across theme and view changes, letting you host custom content (labels, buttons) beneath the calendar.

Article: https://docs.telerik.com/devtools/winforms/knowledge-base/chat-intercept-html-links
Summary: This article shows how to intercept and handle HTML anchor links inside Telerik UI for WinForms RadChat messages by using the MessageFormatting event to access the message’s markup text element and subscribing to its LinkClicked/HyperlinkClicked event. It demonstrates capturing the clicked URL and executing custom logic (for example, open in a browser or cancel navigation) so you can control link behavior per message.

Article: https://docs.telerik.com/devtools/winforms/knowledge-base/chat-resize-wrap-text-cardaction
Summary: This article shows how to make RadChat CardAction text wrap in Telerik UI for WinForms when the control is resized. You implement a custom ChatElementFactory that returns a CardAction element with TextWrap enabled and width-aware measuring (e.g., updating MaxSize on SizeChanged), so long labels break across lines and the card layout reflows correctly.

Article: https://docs.telerik.com/devtools/winforms/knowledge-base/datetimepicker-customizing-footer-panel
Summary: This article shows how to customize the footer panel of the popup RadCalendar used by the Telerik WinForms RadDateTimePicker. You’ll access the calendar’s footer element when the drop-down opens, hide or rename the default Today/Clear buttons, add custom RadButtonElements, wire Click handlers to set the picker’s Value, and close the popup programmatically.

Article: https://docs.telerik.com/devtools/winforms/knowledge-base/grid-custom-filtering-self-referencing-hierarchy
Summary: This article shows how to implement custom filtering in Telerik WinForms RadGridView when using a self-referencing hierarchy (Id/ParentId). You will handle GridViewTemplate.CustomFiltering to evaluate matches across levels, keep parent rows visible when any child satisfies the filter (and optionally the reverse), and preserve the hierarchical structure while applying FilterDescriptors.

Article: https://docs.telerik.com/devtools/winforms/knowledge-base/gridview-snap-one-row-per-scroll
Summary: Learn how to make RadGridView (Telerik UI for WinForms) snap the viewport to full rows, scrolling exactly one row per mouse wheel action. The article shows intercepting MouseWheel to suppress the default pixel-based scroll and using TableElement.RowScroller APIs (optionally aligning VScrollBar.SmallChange to the row height) to implement discrete, row-based scrolling.

Article: https://docs.telerik.com/devtools/winforms/controls/navigationview/kb-related-articles
Summary: This page indexes Knowledge Base articles for the Telerik UI for WinForms NavigationView control. Use it to quickly locate how-to and troubleshooting guidance for configuration, customization, data binding, item population, styling, selection, and event handling.

Article: https://docs.telerik.com/devtools/winforms/ai-coding-assistant/mcp-server-as-nuget
Summary: This article shows you how to add and configure the MCP Server as a NuGet package in a Telerik UI for WinForms project to enable the AI Coding Assistant. You install the package, set up your LLM provider (OpenAI or Azure OpenAI), wire up the server and tools, and initialize it in your app so the assistant can access your workspace and files.

Feel free to check them out and share your thoughts!

The Telerik Team

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

• Aqua
• Breeze
• Desert
• Windows 7
• Office 2007 (Black/Silver)
• Office 2010 (Black/Blue/Silver)
• Office 2013 (Light/Dark)
  

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

1. if i set  MultiSelect = false;     

   after user click

   how can i get current row and it's data

 2. if i set  MultiSelect = true;     

   after user select many rows 

   how can i get these rows and it's data

I use a RadDropDownList, I want to give the user the ability to search the items in the drop down so I use the default DropDownStyle = DropDown with AutoCompleteMode = SuggestAppend.

However, I want to ensure that the user selects a valid item from the list and doesn't leave random text. So I created the extension method EnsureValidSelection() below that remembers the original value, and on validation resets it to that original value if no valid value is now selected.

This works well when the ValueMember is an int. But when it's a string, it ignores the code that sets the SelectedValue.

public static void EnsureValidSelection(this RadDropDownList combo)
{
    object originalValue = null;
    combo.Enter += DropDownEnter;
    combo.SelectedValueChanged += DropDownSelectedValueChanged;
    combo.Validated += DropDownValidated;
    return;

    void DropDownEnter(object sender, EventArgs e)
    {
        originalValue = ((RadDropDownList)sender).SelectedValue;
    }

    void DropDownSelectedValueChanged(object sender, EventArgs e)
    {
        if (originalValue != null && combo.SelectedValue != null)
            originalValue = combo.SelectedValue;
    }

    void DropDownValidated(object sender, EventArgs e)
    {
        if (combo.SelectedValue == null)
            combo.SelectedValue = originalValue;
        originalValue = null;
    }
}

Hi there, I have three panels and I want to hide the centre panel - how do I do this please?

I don't want to just make it zero width - I would like to hide it totally (including the sizing handle) until I need it.

Here is what I have tried thus far...

Me.mSplitContainer.SplitPanels("panFilter").SplitPanelElement.Visibility = Telerik.WinControls.ElementVisibility.Collapsed

Thank you in advance.

Simon

I've got a RadRibbonForm as my main form.  I'd like my users to be able to resize this form - and they can but the border is a single pixel making it nearly impossible to position your mouse over it in order to drag-and-resize.

I've tried creating my own Telerik.WinControls.UI.FormControlBehavior class called "CustomFormControlBehavior" that Inherits Telerik.WinControls.UI.FormControlBehavior with BorderWidth property that looks like this:

Public Overrides ReadOnly Property BorderWidth As Padding
Get
Return New Padding(10)
End Get
End Property

and in my main form's constructor, following InitializeComponent() I've added the following:

        Dim Behavior As Telerik.WinControls.UI.FormControlBehavior = New CARMSCustomRibbonFormBehavior()
        Me.FormBehavior = Behavior

The above code will not execute!

Can you help me resolve how to change the BorderWidth of my RadRibbonForm?  How close was I to the solution!? :)

Kindest regards, all!

-C

I'm using the DockWindow on an MDI WinForms app. The Customer Search form is the first one to open.

When I open another form I'd like it to appear to the right of Customer Search. For some reason its appearing to the left.

The code below shows how I open it. Setting the MDIParent adds it to the DocumentWindows collection.

How can I get the Account form to appear to the right of Customer Search. (And any forms opened after that also must appear to the right.)

FormAccount? form = null;
foreach (HostWindow window in this.dock.DockWindows.DocumentWindows)
	if (window.MdiChild is FormAccount)
	{
		FormAccount formCandidate = (FormAccount)window.MdiChild;
		if (formCandidate.BranchId == GlobalServices.Instance.ActiveBranchID && formCandidate.AccountId == (accountId == null ? GlobalServices.Instance.ActiveAccount.NamesId : accountId))
			form = formCandidate;
	}

if (form == null)
{
	form = accountId == null ? new FormAccount(GlobalServices.Instance) : new FormAccount(GlobalServices.Instance, accountId);
	form.AccountId = GlobalServices.Instance.ActiveAccountID;
	form.MdiParent = this;
	form.SetImageAndTitle(ETitleFormat.Account);
	form.AccountFormType = EAccountFormType.Account;
	form.ControlBox = false;
	form.LaunchedFromIPC = launchedFromIPC;
	if (sender == null)
		this.WindowState = FormWindowState.Maximized;
	form.Show();
}

HostWindow hw = App.MainForm.dock.GetHostWindow(form);
if (hw != null)
	dock.ActivateWindow(hw);

Thanks

Carl

I may have missed someone already talking about this - but for those of us who like to give our users the ability to select their own "Theme" one ugly issue I'm constantly having to deal with is:  When the user changes their theme, I have to manually change the "look" for every Splitter in my application (400+ WinForm classes, there are probably a few thousand "Splitters")

Is there some technical reason there's no "RadSplitter" in the Telerik WinForms library and if there is not, I'd like to suggest that this be added.  It's a super-commonly used WinForm control, I'm a little shocked it's not already present in this spectacular WInForms UI Library!

p.s. using a SplitContainer is often not possible because of downward compatibility with the older app suits but does make a nice alternative for newer forms.

Kindest regards,

LK

Hi there,

I would like to add controls to the navigation portion of the Navigation View if possible. I can place controls in front of the Navigation View (see attached image) but I was hoping to be able to add a panel above or below where the Navigation buttons are that will collapse if the Navigation VIew button section is collapsed. Is this at all possible or should I simply place controls in front of the Nav View as I have put in the image.

Thanking you in advance

Simon