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

Article: https://www.telerik.com/document-processing-libraries/documentation/knowledge-base/convert-heic-images-to-jpg
Summary: Learn how to convert HEIC (.heic/.heif) images to JPEG (.jpg) in C#/.NET so you can process them with Telerik Document Processing. The article explains that HEIC isn’t supported natively, then shows how to decode HEIC via the OS HEIF codecs or a third‑party library and re‑encode to .jpg with a concise code sample. It also notes the required codecs and runtime dependencies you need to include with your application.

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25 Feb to 04 Mar 2026: highlights of the new online resources that we published last week.

Article: https://www.telerik.com/document-processing-libraries/documentation/introduction
Summary: This introduction shows you how to use Telerik Document Processing Libraries in .NET/C# to create, read, modify, and convert documents without Microsoft Office, including DOCX, PDF, XLSX, CSV, HTML, RTF, and TXT. It outlines each library—RadWordsProcessing, RadPdfProcessing, RadSpreadProcessing, RadSpreadStreamProcessing, and RadZipLibrary—their supported formats and platforms, common tasks (e.g., mail merge, PDF forms/signatures, formulas/conditional formatting, large XLSX streaming), and the required NuGet packages and dependencies. Use it to pick the right API and set up server-side or desktop projects on .NET/.NET Core with attention to performance and memory considerations such as streaming export.

Article: https://www.telerik.com/document-processing-libraries/documentation/security/faq
Summary: This Security FAQ for the Telerik Document Processing Libraries clarifies the threat surface and default behavior: the libraries do not execute macros, scripts, PDF JavaScript, or other embedded code, and they do not perform network access—they process only the data you pass in via your code. It outlines how to handle untrusted documents safely (e.g., sandboxing, controlling memory/CPU, sanitizing content), what is and isn’t supported for password-protected documents, and how to stay current and report security issues.

Article: https://www.telerik.com/document-processing-libraries/documentation/knowledge-base
Summary: This page indexes the Knowledge Base for Telerik Document Processing Libraries in .NET, covering RadWordsProcessing, RadPdfProcessing, RadSpreadProcessing, RadSpreadStreamProcessing, and RadZipLibrary. Use it to find focused how-to guides, code snippets, and troubleshooting for tasks like converting DOCX/XLSX to PDF, merging/splitting documents, handling fonts and encodings, digital signatures and forms, streaming large files for performance, and resolving common import/export exceptions and format limitations across WPF, WinForms, ASP.NET Core, and console apps.

Article: https://www.telerik.com/document-processing-libraries/documentation/security/overview
Summary: This overview maps the security features in Telerik Document Processing libraries (PdfProcessing, WordsProcessing, SpreadProcessing, ZipLibrary) and how to use them in code. You will encrypt and password-protect PDF, DOCX, XLSX, and ZIP files, set PDF user/owner passwords and permissions, add digital signatures to PDFs, and protect Word documents and Excel workbooks/worksheets. Use it to choose the right APIs and entry points for implementing document protection in your application.

Article: https://www.telerik.com/document-processing-libraries/documentation/getting-started/next-steps
Summary: After setting up Telerik Document Processing, use this Next Steps page to jump into the specific library you need—WordsProcessing, PdfProcessing, SpreadProcessing, SpreadStreamProcessing, or ZipLibrary—review supported file formats and feature overviews, and find the corresponding NuGet packages and API reference for your .NET/C# project. It aggregates entry points to tutorials and how-to guides for creating, editing, and converting documents, along with code samples/SDK examples, to help you implement document generation and import/export workflows.

Article: https://www.telerik.com/document-processing-libraries/documentation/getting-started/first-steps
Summary: This article walks you through adding Telerik Document Processing to your .NET/C# project via the Telerik NuGet feed—using the meta package or the specific libraries you need (WordsProcessing, PdfProcessing, SpreadProcessing, SpreadStreamProcessing, ZipLibrary). You configure the required format-provider packages, align with supported target frameworks, and write minimal code to create and export your first DOCX, PDF, or XLSX file.

Article: https://www.telerik.com/document-processing-libraries/documentation/upgrade/upgrade-instructions
Summary: Use this guide to upgrade the Telerik Document Processing libraries (PdfProcessing, WordsProcessing, SpreadProcessing, ZipLibrary) in your .NET projects. It shows how to update via the Telerik NuGet feed or local binaries, keep all Telerik.Documents.* and Telerik.Zip packages on the same version, migrate from legacy Telerik.Windows.Documents assemblies/namespaces, add binding redirects for .NET Framework, and clean bin/obj before rebuilding. It also covers common post-upgrade issues (duplicate type/assembly conflicts, missing format providers) and how to resolve them.

Article: https://www.telerik.com/document-processing-libraries/documentation/ai-tools/agent-tools/overview
Summary: Learn how to expose Telerik Document Processing Libraries operations to LLM agents using Agent Tools—covering document creation, editing, conversion, and controlled file I/O—with built-in tools for WordsProcessing, SpreadProcessing, and PdfProcessing. You will register and configure tools in .NET, restrict file-system access, serialize tool definitions for LLM function-calling, and execute tool calls. The article also shows how to implement and register custom tools to extend agent capabilities.

Article: https://www.telerik.com/document-processing-libraries/documentation/knowledge-base/before-q2-2025
Summary: This article explains what you need to do before upgrading to the R2 2025 (Q2 2025) release of Telerik Document Processing. It summarizes breaking changes and deprecations across WordsProcessing, PdfProcessing, SpreadProcessing, SpreadStreamProcessing, and ZipLibrary, and shows how to update your NuGet references, target frameworks, and affected APIs so your projects continue to build and run.

Article: https://www.telerik.com/document-processing-libraries/documentation/knowledge-base/convert-to-pdf
Summary: Use Telerik Document Processing in .NET to convert to PDF: import DOCX/RTF/HTML into a RadFlowDocument and export with WordsProcessing PdfFormatProvider; import XLSX/CSV into a Workbook and export with SpreadProcessing PdfFormatProvider; and generate PDFs (including from images) with PdfProcessing using RadFixedDocument and PdfWriter. The article provides C# patterns using streams, format providers, page setup, and font embedding to control the resulting PDF.

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

Article: https://docs.telerik.com/devtools/document-processing/ai-tools/agent-tools/agent-tools-convert-merge-document-api
Summary: Use the Telerik Document Processing AI Agent Tools Convert and Merge Document API to convert documents between supported formats and optionally merge multiple inputs into a single file. The article details the request/response schema, supported formats (e.g., DOCX, RTF, HTML, PDF, XLSX, CSV), and how to call it from C#: pass files from disk or streams, set the target format and merge order, handle password-protected content, and retrieve the output file.

Article: https://docs.telerik.com/devtools/document-processing/ai-tools/ai-coding-assistant/changelog
Summary: This page provides the AI Coding Assistant changelog for Telerik Document Processing, with version-by-version release notes covering new features, improvements, bug fixes, and any breaking or deprecated changes. Use it to track what changed in each release, verify compatibility and prerequisites, and plan updates to your workflows or code that use the assistant.

Article: https://docs.telerik.com/devtools/document-processing/ai-tools/agent-tools/getting-started
Summary: Learn how to set up Telerik Document Processing AI Tools – Agent Tools in .NET so your LLM/agent can call document processing operations as tools. You’ll add the required NuGet packages, configure dependencies, initialize the tools, and run a minimal C# example to validate the integration.

Article: https://docs.telerik.com/devtools/document-processing/ai-tools/ai-coding-assistant/mcp-server-as-a-nuget
Summary: This guide shows you how to install and self-host the Telerik AI Coding Assistant MCP (Model Context Protocol) server as a NuGet package in a .NET project. You will add the package, configure and start the host to expose Telerik Document Processing tools over MCP, set server options (such as port and endpoints), and connect an MCP client to validate the setup.

Article: https://docs.telerik.com/devtools/document-processing/ai-tools/ai-coding-assistant/mcp-server
Summary: Learn how to install and run the Telerik Document Processing AI Coding Assistant MCP server to expose document-processing tools over the Model Context Protocol. You’ll configure the server and tool set (WordsProcessing, PdfProcessing, SpreadProcessing) and connect it to an MCP-compatible client so an LLM can create, convert, inspect, and edit Word, PDF, and spreadsheet files via tool calls. The guide covers prerequisites, configuration options, and how to verify and use the available commands.

Article: https://docs.telerik.com/devtools/document-processing/ai-tools/agent-tools/multi-user-scenario
Summary: This article shows you how to run Telerik Document Processing AI Tools (Agent Tools) in a multi-user environment by isolating agent state and resources per user or conversation and avoiding shared mutable state across requests. You’ll configure ASP.NET Core dependency injection to create scoped agent and tool instances, set up per-user storage and configuration, and handle concurrency and lifetime management for safe, predictable operation.

Article: https://docs.telerik.com/devtools/document-processing/ai-tools/agent-tools/overview
Summary: You’ll learn how to expose Telerik WordsProcessing, PdfProcessing, SpreadProcessing, and ZipLibrary features as callable tools for LLM agents in .NET. The article covers prerequisites and NuGet setup, initializing a toolset, and registering tools so your agent can read, extract, convert, and save DOCX, PDF, XLSX, and ZIP content. It also outlines configuration for controlled file access and usage patterns you can plug into your agent framework.

Article: https://docs.telerik.com/devtools/document-processing/ai-tools/ai-coding-assistant/overview
Summary: Learn how to use the AI Coding Assistant to generate and refine .NET code for Telerik Document Processing libraries—WordsProcessing, PdfProcessing, SpreadProcessing, and ZipLibrary. You select a task, use the provided prompt with your preferred LLM (e.g., ChatGPT or Azure OpenAI), and get C# or VB.NET snippets with the required API usage and package references. The overview also notes supported scenarios, prerequisites, and limitations so you can integrate the output safely into your project.

Article: https://docs.telerik.com/devtools/document-processing/ai-tools/agent-tools/pdf-document-api
Summary: This article documents the PDF Document API agent tool in Telerik Document Processing, which exposes PdfProcessing capabilities to your .NET/C# agent or function-calling workflows. It explains how to configure and call tool actions to load and save PDFs from the agent file store and perform tasks such as getting page count and metadata, extracting text and images, splitting or merging pages, working with form fields, and exporting results, including the action names, parameters, and input/output schemas.

Article: https://docs.telerik.com/devtools/document-processing/ai-tools/ai-coding-assistant/prompt-library
Summary: This page catalogs the AI Coding Assistant Prompt Library for Telerik Document Processing, with task-oriented prompt templates that generate C# for RadPdfProcessing, RadWordsProcessing, RadSpreadProcessing, SpreadStreamProcessing, and ZipLibrary. You can run prompts in the assistant, review required inputs/placeholders and expected outputs, and add or customize prompts for your .NET projects. Use it to implement operations like creating PDFs, manipulating DOCX, editing or streaming XLSX files, and compressing archives with the Document Processing APIs.

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

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/spreadprocessing-insert-image-cell-range-aspect-ratio
Summary: Learn how to insert an image into a specific cell range in Telerik Document Processing (SpreadProcessing) while preserving the image’s aspect ratio. You’ll compute the range size from column widths and row heights, scale the image to fit, and create a FloatingImage anchored by top-left and bottom-right cell indices (Placement = MoveAndSize) so it stays within the range and resizes with cells.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/spreadprocessing-open-locked-files-read-only
Summary: This article shows how to open a locked Excel file in read-only mode with Telerik Document Processing (SpreadProcessing). You create a C# FileStream with FileAccess.Read and FileShare.Read or FileShare.ReadWrite and pass it to XlsxFormatProvider.Import to avoid “in use by another process” IOExceptions; then work with the in-memory Workbook and, if needed, save to a different path.

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

Article: https://docs.telerik.com/devtools/document-processing/common-information/fileformatdetector
Summary: Use FileFormatDetector to identify a document’s format from a file path or Stream so you can route it to the correct Telerik Document Processing format provider. It recognizes WordsProcessing (DOCX/RTF/HTML/TXT), SpreadProcessing (XLSX/CSV/TXT), and PDF formats; after detection, use the corresponding provider (e.g., DocxFormatProvider, XlsxFormatProvider, PdfFormatProvider) and, if detecting from a Stream, reset its position before loading.

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

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/accessing-specific-cells-radspreadstreamprocessing
Summary: Explains how to write to a specific cell with RadSpreadStreamProcessing by creating the row and cell exporters with explicit row and column indexes during forward-only export, then setting the cell value. Clarifies that the streaming API does not support random access or reading/updating previously written cells, and suggests using RadSpreadProcessing if you need to query or modify arbitrary cells.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/create-bullet-list-using-paragraph-styles-radwordsprocessing
Summary: Learn how to create bulleted lists in Telerik RadWordsProcessing by defining a DocumentList and binding it to a paragraph style, so you can apply bullets by setting StyleId instead of per-paragraph list properties. The article walks you through creating a bulleted DocumentList (e.g., ListStyle.BulletDefault), setting ParagraphProperties.ListId and ListLevel in a StyleDefinition, and applying the style to generate single- or multi-level bullets with consistent indentation in programmatically generated DOCX.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/how-to-deal-with-fonts-net-framework-net-standard-pdf-export
Summary: Learn how font resolution differs between .NET Framework and .NET Standard/.NET Core when exporting PDFs with Telerik PdfProcessing, and why missing system fonts lead to substitutions and inconsistent output. The article shows how to explicitly register and embed font files (via the fonts repository/provider) and configure fallback behavior, so you can ship fonts with your app and produce consistent PDFs across Windows, Linux, and macOS, including containerized servers.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/processing-decimal-columns-as-double-from-datatable
Summary: If you import a DataTable into Telerik Document Processing (SpreadProcessing), convert decimal columns to double so values are written as numeric cells instead of text. Detect DataColumn types of decimal and cast to double (or replace the column with typeof(double) using invariant culture) before calling Worksheet.Cells.SetValue, ensuring calculations, numeric formatting, and XLSX export behave correctly.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/saving-data-from-datagridview-to-xlsx-file-in-csharp
Summary: Learn how to export WinForms DataGridView data to an Excel .xlsx file in C# using Telerik Document Processing (SpreadProcessing), without Excel interop. You create a Workbook and Worksheet, copy column headers and rows by iterating the DataGridView or its DataSource, and save the workbook to disk with XlsxFormatProvider.

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

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/retain-numeric-values-datatable-excel-datatableformatprovider
Summary: Learn how to preserve numeric types when moving data between a DataTable and Excel using Telerik Document Processing (SpreadProcessing) DataTableFormatProvider. You’ll set DataColumn.DataType to a numeric type (e.g., int, double, decimal) or pre-convert string columns before calling DataTableFormatProvider.Import/Export so numbers are written as Number cells instead of text. The article includes a C# example to convert columns and avoid losing numeric semantics during export/import.

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

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/avoiding-format-symbol-conversion-cellvalueformat
Summary: This article explains how to prevent automatic conversion of Excel format symbols when you set CellValueFormat in Telerik SpreadProcessing, so your custom number/date formats are preserved as intended. It shows practical ways to keep symbols literal—using the Text ('@') format where appropriate and escaping or quoting characters in the format string—to avoid locale-specific mapping and unintended reformats.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/converting-html-to-image-using-document-processing
Summary: This article shows how to convert HTML to images in .NET with Telerik Document Processing: import HTML into a RadFlowDocument using WordsProcessing’s HtmlFormatProvider, export to PDF, then convert the PDF pages to images (e.g., multi-page TIFF) via PdfProcessing’s TiffFormatProvider. It includes C# examples, notes on supported HTML/CSS, and guidance for controlling page size, DPI, and per-page image output.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/docxformatprovider-line-spacing-font-size-changes
Summary: This article explains why line spacing and font sizes can change when importing or exporting DOCX with Telerik WordsProcessing DocxFormatProvider, focusing on WordprocessingML defaults (lineRule=auto/multiple/exact), unit conversions (w:sz in half-points, w:line in twips), and theme/complex-script font settings. It shows how to preserve formatting by explicitly setting ParagraphProperties.Spacing.LineSpacingType and LineSpacing to match Word (e.g., Multiple=1.15) and by defining RunProperties.FontSize and styles rather than relying on document defaults.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/fix-missing-pdf-content-german-culture
Summary: Learn why PDFs generated with Telerik Document Processing (PdfProcessing) can show missing content under German (de-DE) culture: numeric values get formatted with a comma decimal separator, breaking PDF content streams. Fix it by enforcing CultureInfo.InvariantCulture during PDF creation/export (e.g., set Thread.CurrentThread.CurrentCulture or DefaultThreadCurrentCulture to InvariantCulture) so numbers use a dot and the content renders correctly.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/handling-empty-cells-when-reading-excel-rows-using-radspreadstreamprocessing
Summary: Learn how to handle empty cells when reading Excel (XLSX) rows with Telerik RadSpreadStreamProcessing: the streaming reader returns only populated cells, skipping blanks. The article shows how to use each cell’s ColumnIndex and the worksheet dimension to detect gaps and insert placeholders, preserving column alignment for leading, middle, and trailing empty cells during parsing.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/handling-local-path-images-html
Summary: Learn how to import HTML that uses local file system image paths with Telerik Document Processing. You’ll implement and register a custom image resolver in the HtmlFormatProvider import settings to read image data from disk (handling absolute and relative paths via a base directory) and supply it to WordsProcessing/PdfProcessing so elements are embedded correctly.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/radpdfprocessing-draw-pdf-page-background
Summary: Learn how to draw a PDF page background with Telerik RadPdfProcessing by using FixedContentEditor to render a full-page rectangle or image sized to RadFixedPage.Size. The article explains computing the page bounds, calling DrawRectangle or DrawImage to cover the entire page, and adding the background first in the content stream to keep it behind subsequent content.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/radspreadprocessing-protect-specific-worksheet-cells
Summary: Use Telerik Document Processing (RadSpreadProcessing) to protect specific worksheet cells by setting the IsLocked flag on the desired cell ranges and then enabling worksheet protection with an optional password and granular permissions. The article provides C# code that unlocks all cells, locks targeted ranges, and configures protection options so only selected cells remain editable while actions like formatting or inserting rows are restricted.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/radwordsprocessing-change-bookmark-content-preserve-formatting
Summary: Learn how to replace the text inside a bookmark in Telerik RadWordsProcessing (WordsProcessing) without losing formatting. You locate the bookmark boundaries (BookmarkRangeStart/BookmarkRangeEnd), create a DocumentRange, and use RadFlowDocumentEditor to split affected runs and update their Text so existing inline and paragraph styles (fonts, bold, color, etc.) remain intact. The article provides C# code you can adapt to update bookmark content while preserving all formatting.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/radwordsprocessing-modify-content-of-content-controls
Summary: This article shows how to use Telerik RadWordsProcessing to modify Word content controls (structured document tags) in DOCX files. It walks you through importing with DocxFormatProvider, locating inline and block content controls in a RadFlowDocument (e.g., by Tag or Title), updating their inner content (runs, paragraphs, checkbox state), and exporting the changes.

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

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/handle-missing-content-in-nested-tables-while-converting-docx-to-pdf
Summary: You’ll learn why content in nested tables can disappear when converting DOCX to PDF with Telerik Document Processing (WordsProcessing), typically due to auto-fit/automatic width calculations in nested tables that the PDF layout engine can’t resolve. The article shows how to prevent this by explicitly setting fixed widths on the outer and inner tables or disabling AutoFit before export, with C# examples to adjust PreferredWidth/column widths so all content renders in the PDF.

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01 Dec to 08 Dec 2025: highlights of the new online resources that we published last week.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/fix-invalid-license-watermark-and-framework-mismatch-telerik-document-processing
Summary: Learn how to diagnose and fix “Invalid product license” watermarks and framework mismatch errors when using Telerik Document Processing (PdfProcessing, WordsProcessing, SpreadProcessing). Ensure you aren’t mixing trial and commercial builds or .NET Framework binaries with .NET Standard/.NET binaries, and keep all Telerik.Documents.* and Telerik.Zip references on the same version aligned to your target framework. Reinstall from the correct NuGet feed, replace any legacy Telerik.Windows.Documents.* references, clear bin/obj and NuGet caches, then rebuild to remove the watermark and resolve load/runtime errors.

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24 Nov to 01 Dec 2025: highlights of the new online resources that we published last week.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/registering-custom-font-variations-pdf-processing
Summary: Register custom font variations in RadPdfProcessing by mapping FontFamily, FontStyle, and FontWeight to specific TTF/OTF files via FontsRepository.RegisterFont, ensuring the correct face is embedded in your PDFs. The article explains the supported style/weight pairs (Normal/Bold and Normal/Italic) and shows how to route other weights like Light or SemiBold to those mappings using FontFileSource.

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

Summary: This changelog provides versioned release notes for the Telerik Document Processing AI Coding Assistant, including dates, new features, enhancements, and fixes. Use it to track changes and compatibility, plan upgrades, and troubleshoot behavior across versions in your projects.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/changing-date-format-exported-excel-blazor-grid
Summary: Explains how to change the date format in an Excel export from a Telerik UI for Blazor Grid by post-processing the generated workbook with Telerik Document Processing (SpreadProcessing). You handle the grid’s Excel export event, target DateTime columns or cells in the worksheet, and apply a CellValueFormat/NumberFormat (e.g., yyyy-MM-dd) so Excel displays consistent date values instead of locale-specific text or serial numbers.

Article: https://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/gen-ai-powered-document-insights/complete-context-question-processor
Summary: This article explains how to use the RadSpreadProcessing Gen‑AI Complete Context Question Processor to answer natural-language questions over a workbook using the full spreadsheet context (cells, evaluated formulas, named ranges, tables, charts, and pivot tables). It covers configuring LLM and embeddings providers, building the document context/index from a Workbook, and invoking the API to get answers with cell/range citations, plus options for scope control, retrieval depth, and token limits.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/consistent-pdf-font-formatting
Summary: This article shows how to achieve consistent PDF font formatting when exporting with Telerik Document Processing (PdfProcessing/WordsProcessing). You register the complete font family (regular, bold, italic, bold-italic) via FontsRepository/FontsSettings, configure PdfExportSettings to embed fonts, and set explicit substitution/fallback fonts to avoid viewer-dependent faux styles and glyph fallback. These steps prevent mismatched fonts, weights, and glyphs across machines and PDF viewers.

Article: https://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/gen-ai-powered-document-insights/custom-partialcontextquestionprocessor
Summary: This article shows how to implement and register a custom PartialContextQuestionProcessor in RadSpreadProcessing GenAI Document Insights to control partial context extraction from spreadsheets. You define logic to select relevant worksheets, ranges, tables, or metadata, override the context-building methods, and configure InsightsOptions so only the needed cells are sent to the LLM.

Article: https://docs.telerik.com/devtools/document-processing/libraries/radwordsprocessing/editing/gen-ai-powered-document-insights/custom-partialcontextquestionprocessor
Summary: This article shows how to implement a custom PartialContextQuestionProcessor in Telerik Document Processing (RadWordsProcessing) to control document context extraction for question answering and to tailor LLM prompt composition and token limits. It details the overrides and wiring to register the processor in the Gen-AI Document Insights pipeline and use it with OpenAI or Azure OpenAI providers.

Article: https://docs.telerik.com/devtools/document-processing/libraries/radpdfprocessing/features/gen-ai-powered-document-insights/custom-partialcontextquestionprocessor
Summary: This article shows you how to implement and register a custom PartialContextQuestionProcessor in RadPdfProcessing’s Gen AI–powered Document Insights to control which PDF segments are selected and sent to an LLM. You’ll learn how to plug in your own retrieval and prompt-building logic, tune context size and relevance filtering, and integrate the processor into the Document Insights workflow to tailor PDF question answering to your model and token budget.

Article: https://docs.telerik.com/devtools/document-processing/libraries/radpdfprocessing/features/digital-signature/external-digital-signing
Summary: RadPdfProcessing supports external digital signing of PDFs, letting you compute the signing hash for a SignatureField, send it to an HSM or remote key service, and then embed the returned CMS/PKCS#7 signature to finalize the document. The article details the two-phase workflow, required API calls, ByteRange handling, and supported hash algorithms (e.g., SHA-256) for integrating external signers.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/fit-multiline-text-stamp-annotation-radpdfprocessing
Summary: This article explains how to render multiline, wrapped text inside a Telerik Document Processing RadPdfProcessing StampAnnotation by creating a custom appearance stream and drawing the text with FixedContentEditor. It covers measuring text widths, breaking lines to fit the annotation’s rectangle, configuring font/margins/alignment, and assigning the Normal appearance so the stamp renders correctly in PDF viewers.

Article: https://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/gen-ai-powered-document-insights/getting-started
Summary: This guide shows how to configure and use Gen AI Powered Document Insights in Telerik Document Processing (RadSpreadProcessing) to programmatically analyze workbook data and ask questions about spreadsheets. It covers setup steps—adding required packages, configuring an AI provider, and enabling insights for a workbook or worksheet—and demonstrates calling the API to return structured answers with references to cells and ranges. The article includes .NET code samples to initialize the service and run queries.

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

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/alternating-row-color-in-pdf-tables
Summary: Implement alternating row colors (zebra striping) in PDF tables with Telerik RadPdfProcessing (PdfProcessing) in C# by setting row or cell background fills during table generation. Use the FixedContentEditor/Table API and the row index (e.g., row % 2) to differentiate header and data rows and apply consistent styling in a RadFixedDocument.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/generate-pdf-with-headers-footers-from-separate-html-files
Summary: Learn how to generate a PDF with repeating headers and footers from separate HTML files using Telerik Document Processing (WordsProcessing) in C#. You import body, header, and footer HTML with HtmlFormatProvider into RadFlowDocument instances, copy the header/footer content into the target document’s Section.Headers/Footers, then export to PDF with PdfFormatProvider.

Article: https://docs.telerik.com/devtools/document-processing/getting-started/installation/generating-api-keys
Summary: This guide shows you how to generate and manage API keys in your Telerik account to authenticate against the private Telerik NuGet feed for installing Telerik Document Processing packages. You’ll create a key (with optional expiration), copy it, and configure it in nuget.config, Visual Studio, or the dotnet/nuget CLI for local development and CI/CD, including how to revoke or rotate keys when needed.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/pdfprocessing-prevent-font-conversion-embedding-fonts
Summary: To stop Telerik Document Processing PdfProcessing from converting your text to a different font or to outlines, register your TrueType/OpenType fonts with FontsRepository (for example, via FontsRepository.RegisterFont) and enable embedding when you export the RadFixedDocument. The article shows the code you need to register and use custom fonts, how to control embedding via export settings, and what to do when a font’s licensing prevents embedding and triggers fallback or outline conversion.

Article: https://docs.telerik.com/devtools/document-processing/knowledge-base/read-folder-encrypted-archive
Summary: This article shows you how to read and extract a specific folder from a password‑protected ZIP using Telerik Document Processing ZipLibrary in .NET. You iterate archive entries that match the target folder path and provide decryption settings (password) when opening each entry to stream out the files, handling directory structure creation as needed.

Feel free to check them out and share your thoughts!

The Telerik Team

As the subject says, when using

  using (Stream output = new FileStream(excelFileInfo.FullName, FileMode.OpenOrCreate, FileAccess.Write))
  {
      new XlsxFormatProvider().Export(workbook, output);
  }

Sometimes the resulting Excel file is corrupted and cannot be imported again. I couldn't figure out a pattern so far because it is not with every export of changes in the excel workbook. This issue appears at least since Telerik Version 2025.4.1321.80

The issue seems not to appear in Telerik Version 2024.2.426.70 or earlier.

When the file is corrupted, opening in MS Excel shows the repair dialog.

Attempting to import it via Telerik XlsxFormatProvider throws an Exception:

System.IO.InvalidDataException: Number of entries expected in End Of Central Directory does not correspond to number of entries in Central Directory.

It seems to be some issue with the internal Zip File handling.

Stack Trace:

   at System.IO.Compression.ZipArchive.ReadCentralDirectoryPostOuterLoopWork(Int64 numberOfEntries)
   at System.IO.Compression.ZipArchive.ReadCentralDirectory()
   at System.IO.Compression.ZipArchive.get_Entries()
   at Telerik.Windows.Documents.FormatProviders.OpenXml.OpenXmlImporter`1.GetZipEntries(ZipArchive archive)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.OpenXmlImporter`1.Import(Stream input, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.XlsxFormatProvider.ImportOverride(Stream input, CancellationToken cancellationToken)
   at Telerik.Windows.Documents.Spreadsheet.FormatProviders.WorkbookFormatProviderBase.Import(Stream input, Nullable`1 timeout)

After upgrading the Telerik Document Processing libraries to version Q1 2025 the following error messages may occur:

* "The file or assembly cannot be loaded 'Telerik.Licensing.Runtime, Version=1.4.6.0, Culture=neutral, PublicKeyToken=token_here' or one of its dependencies. The system cannot find the specified file."

* "NU1101: Unable to find package Telerik.Licensing. No packages exist with this id in source(s): Telerik nuget. PackageSourceMapping is enabled, the following source(s) were not considered: Microsoft Visual Studio Offline Packages, nuget.org."

When previewing PDF documents using RadPdfView (Telerik UI for WPF), the logo positioned at the top-left corner of the page fails to render consistently across machines. While the rest of the document displays correctly, the logo either appears distorted or is missing entirely.

Environment:

• Control Used: RadPdfView (Telerik UI for WPF)
• Telerik Libraries:
  • Telerik.Windows.Documents.dll – Version 2023.1.315.45
  • Telerik.Windows.Documents.Core.dll – Version 2023.1.307.40
• Operating Systems Tested:
  • Windows 10 Pro: Logo appears stretched and centered
  • Windows 11 Pro (Version 25H2, OS Build 26200.6899): Logo is missing

Symptoms:

• The logo, embedded in the PDF and originally positioned at the top-left corner, does not render correctly in RadPdfView.
• The issue is isolated to RadPdfView; the same PDF displays the logo correctly in WebView2 and standard web browsers.

Troubleshooting Steps Taken:

• Verified that the logo is present when viewed in other PDF viewers.
• Tested across multiple machines using identical code and PDF files.

Temporary Workaround:
Using <wv2:WebView2> to preview the PDF resolves the issue, indicating that the problem is specific to RadPdfView’s rendering engine.

Request:
Please confirm whether this is a known issue with the specified Telerik versions and advise if a fix or recommended workaround is available to ensure consistent logo rendering in RadPdfView across platforms.

Note: Using .NET version 4.8

The contents of an uploaded .docx file is being cut-off when converted to .pdf file.

Code snippet:

var fileFormatProvider = new Telerik.Windows.Documents.Flow.FormatProviders.Docx.DocxFormatProvider();

using (MemoryStream inputFileStream = new MemoryStream())
{
    this.fileSystemService.GetFile(documentInfo, inputFileStream);
    if (fileFormatProvider != null)
    {
        var document = fileFormatProvider.Import(inputFileStream);

        using (MemoryStream output = new MemoryStream())
        {
            var pdfProvider = new Telerik.Windows.Documents.Flow.FormatProviders.Pdf.PdfFormatProvider();

            pdfProvider.Export(document, output);
            var newFile = new DocumentInfo()
            {
                NameWithPath = outputFileName,
                DocumentLocation = documentInfo.DocumentLocation
            };
            this.fileSystemService.SaveFile(newFile, output);
        }
    }
 

Can someone confirm if this a Telerik side issue, or am I missing a setting or config?

Thanks!

Can someone help me figure out what is wrong here?  I'm getting ad horribly vague Null exception.

var docxProvider = new Telerik.Windows.Documents.Flow.FormatProviders.Docx.DocxFormatProvider();
var pdfProvider = new Telerik.Windows.Documents.Flow.FormatProviders.Pdf.PdfFormatProvider();
RadFlowDocument document = new RadFlowDocument();
byte[] docBytes = File.ReadAllBytes(path);

document = docxProvider.Import(docBytes);    ERROR HERE

var resultBytes = pdfProvider.Export(document);

File.WriteAllBytes(resultPath, resultBytes);

The document i'm trying to load contains tables and images within the tables (jpeg barcodes)

I have verified that pretty much every other tool i use can read the file without issue. 

The goal is ultimately to export the file as a PDF.

Error details:

{"Object reference not set to an instance of an object."}

firstly loading the document i have use 
  // Load the PDF document
  var provider = new PdfFormatProvider();
  var loadedDocument = provider.Import(inDocByte,null);

and after some functinality to export the document i have used below 

 Telerik.Documents.ImageUtils.ImagePropertiesResolver defaultImagePropertiesResolver = new Telerik.Documents.ImageUtils.ImagePropertiesResolver();
 Telerik.Windows.Documents.Extensibility.FixedExtensibilityManager.ImagePropertiesResolver = defaultImagePropertiesResolver;
 provider.Export(document, memoryStream, null);
 outDocPdf = memoryStream.ToArray();

what was the problem can you tell me the solution for that exception