GroupDocs.Comparison for .NET Library – Compare Two Word Documents in C# / ASP.NET

GroupDocs.Comparison for .NET LogoNeed to merge / compare two Word documents in .NET (C#, VB.NET)? GroupDocs.Comparison is the solution you might be looking for. It is a lightweight .NET library for generating diffs between two versions of a document. The library merges documents, compares their contents and styles, provides you with a complete list of changes found and also generates a diff view through a convenient web UI.

The UI can be easily integrated in any ASP.NET project, including MVC and WebForms. Merged documents are displayed through the UI with the diff view approach similar to Microsoft Word's change tracking feature. End users can view compared documents from any modern browser without having to install any plugins or 3rd party software.

If your application does not produce a UI, you can simply use the ComparisonService to process documents in the console or a desktop app.

Supported File Formats

The library allows you to merge / compare up to 3 Word documents. You can compare DOC vs DOC, DOCX vs DOCX and DOC vs DOCX. In addition to that, the library allows you to compare two PDF, Excel (XLS, XLSX), PowerPoint (PPT, PPTX), plain text (TXT), OpenDocument (ODT) or HTML files.

Compare Text & Formatting

The library recognizes changes in text, tables, headers, footers, footnotes and even styles formatting. The last option is currently available only for Microsoft Word documents and recognizes changes in font type, size and style, such as bold, italic, underline, strike-through, etc.

Style changes detected with GroupDocs.Comparison for .Net

Compare 3 Versions of a Word Document

In console mode, GroupDocs.Comparison can compare up to 3 Word documents at once. To enable the feature, use the following code in place of the TargetFileName method of the ComparisonService instance:


Let's now take a quick look at two simple scenarios of how the library can be used. As I already mentioned, the library can work both in conjunction with the diff view web UI and in a desktop environment.

Displaying Diffs through the User Interface

Assume we have an MVC application. There are few things that have to be configured to deploy the library. First, in the Application_Start of your Global.asax, you need to set the base and license paths. Also, please remember to initialize GroupDocs.Comparison:

Once this is done, on the view template you will be able to launch document comparison with the following lines of code:

This code is for the Razor template engine. Also, please don't forget to include JavaScript and CSS resources on the page.

Comparing Documents in a Desktop Environment

To process files in a desktop application you have to follow the same pattern: first, configure and initialize the library then launch the document comparison mechanism:

Basically, all comparison operations in the console version are the same as in the UI one. The Compare method returns a set of found changes that you may then process yourself. One thing that is different in the UI scenario from the console one is that all document processing operations are performed through the ComparisonService instance:


For more details on the library and to download a free evaluation copy, please visit the product's homepage. We also prepared documentation and project samples to help you get started quickly. Feel free to contact us for any deployment assistance or feature requests.

Convert Back and Forth Between 50+ Document Formats in VB.NET & C#: Word to PDF, PDF to Image, HTML to PDF and More

GroupDocs.Conversion for .NET Library - IconGroupDocs.Conversion for .NET is one of emerging products in the GroupDocs product family. GroupDocs.Conversion allows users to convert documents to and from over 50 different formats, including Word (DOC, DOCX) to PDF, PDF to image (TIFF, JPG), HTML to PDF, Word to HTML and many more.

Unlike most of the software on the market, GroupDocs.Conversion is a .NET middleware designed specifically for easy integration into other applications. Thanks to its flexible API, GroupDocs.Conversion can be used in any .NET application: desktop-based (like console apps, WinForms, WPF and Windows services) and web-based (ASP.NET, including WebForms and MVC).

In one of our earlier articles we discovered some of the key features and benefits of this library. In particular, GroupDocs.Conversion allows fast on-the-fly conversion and provides a number of interesting features designed especially for ASP.NET. For example, progress callbacks let the calling webpage know when a conversion has been completed.

In this introduction article I'd like to show you basic and advanced usage of the GroupDocs.Conversion for .NET library in several types of applications.

Go to the article >>>

GroupDocs.Viewer for Java can now be seamlessly integrated into Your Joomla! Website

GroupDocs.Viewer for Java iconWe're glad to announce the release of the GroupDocs.Viewer for Java extension for Joomla!. Developers who work with the Java version of our HTML5 document viewer can now seamlessly integrate it into Joomla! websites. The extension has been approved by the Joomla! marketplace team and is available for download from the official Joomla! marketplace.

With the GroupDocs.Viewer integrated into Joomla!, you can easily embed and display all documents supported by the viewer on your Joomla! web-pages. These include: PDF and Word documents, Excel spreadsheets, PowerPoint presentations, Visio diagrams, CAD files, raster images and a lot more - over 50 file formats in total. Documents can be embedded to a web-page along with the GroupDocs.Viewer's UI, which allows users to conveniently navigate large documents right on a web-page.

The extension is free for developers who have a GroupDocs.Viewer for Java license. If you don't have a license yet, but would like to test the Java version of the GroupDocs.Viewer on your Joomla! website, please download a free evaluation copy of the library from this page.

For more details on the extension, please visit the Joomla! marketplace.

GroupDocs.Comparison for .NET – C# Diff Library for Comparing Text Files

GroupDocs.Comparison for .NetThe GroupDocs.Comparison for .NET is a C# diff library which allows you to merge and compare different versions of a text file and display differences between them through a diff view UI. The library is smart enough to detect both context and style changes. It can be used to compare almost all common text file types, including: PDF, Microsoft Word (DOC, DOCX), Excel (XLS, XLSX), PowerPoint (PPT, PPTX), plain text files (TXT), OpenDocument (ODT) and HTML.

The library merges uploaded text files and then displays diffs between them with a redline view approach - similar to Microsoft Word's change tracking view. Merged documents are rendered trough the web UI with pure HTML5, JavaScript and CSS. This allows end users to see differences between the compared text files using any modern web-browser.

GroupDocs.Comparison is a 100% independent C# diff library - there is no need to install Microsoft Office, Adobe Acrobat or any other software either on server or client side. Thanks to the flexible API, you can use GroupDocs.Comparison with your own UI or in the console and any types of web, mobile and desktop apps.

We've already presented the library to our regular readers. Since then the library has seen a number of exciting improvements. Today, we'd like to discuss them in detail.

Support for Streams

The latest version of the diff library was enhanced with an ability to read text files from streams. Now you can easily connect it to your service or implement a complex project with documents hosted anywhere you need. Stream initialization works the following way:

Flexible API for Easy Integration Into Your Workflow

Although the diff view UI that comes with the library is 100% customizable, you can use the flexible API to build your own UI from scratch, or even use the library without the UI and compare documents on the server-side:

Diff Text Styles

In addition to context differences, GroupDocs.Comparison can now identify changes in text styles, including bold, italic, underline, strike-trough, font changes, etc.

GroupDocs.Comparison Diff UI - Compare Text Styles

Accept and Reject Changes in Word Files

Differences found between Word (DOC, DOCX) files can be accepted or rejected right in a web UI and the result can be then exported to a final document in DOC/DOCX format.

GroupDocs' C# Diff Library - Accepting and Rejecting Changes

Merge & Compare Up to 3 Word (DOC, DOCX) Files

The library allows you to compare up to 3 versions of a Word file and generate a merged results file. You can also see which diffs came from what version of the file.

Send Result Documents to Streams

Now you can send merged documents and the diff details to streams, without having to write these directly to an output file.

Diff Summary Tumbler

In case you don't need a summary with a list of all differences to be included in the resulting file, you can now disable this feature easily:

Enhanced Sample Project in C#

We've updated our demo written in C# to reflect the latest features and help you get started with the diff library quickly. Please feel free to download the demo from this page.


For more details on the diff library, please visit its homepage. Also, download a free evaluation copy and a demo. If you'd like to test the library without any functional restrictions, please contact sales for a free 30-day license. We also offer free deployment support, so please don't hesitate to contact us - we'll be happy to help.

Product updates and roadmap: news from GroupDocs, July 2014

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Monthly Newsletter
July, 2014
Securely Sign Documents in the Cloud
GroupDocs.Signature for Cloud is an API that allow developers to add secure e-signature features to their apps. Platform and language independent, the API supports different types of signatures, a variety of workflows, reminder management, contact management and signer roles.
Product News
GroupDocs.Viewer for .NET Library

  • Improved performance when viewing large documents.
  • DWG file format support.
  • Support for Amazon S3 and Azure storage.

GroupDocs.Viewer for Java Library

  • Support for TIFF Files.
  • Added parameters to improve watermark handling, PDF printing and page reordering.
  • Support for relative application path.
  • Support for switching browser cache.
  • Simpler license verification when GroupDocs.Viewer is used in another application.
  • Fixes for various issues.

GroupDocs.Annotation for .NET Library and Cloud App

  • DWG file format support.
  • Redacting (blacking out) text.
  • Hiding tools.
  • Print view with annotations.
  • Support for Amazon S3 and Azure storage (.NET).

GroupDocs.Annotation for Java Library

  • User interface improvements.
  • Arrow annotation type added.
  • Support for importing comments and replies on point, area, text and polyline annotations.
  • General fixes.

GroupDocs.Signature for Cloud App

  • Take signer photo for authentication when signing envelope.
  • Add comments to envelopes.
  • A variety of bug fixes.

GroupDocs.Signature for .NET Library

  • Use stream for input and output when signing.
  • Various issues fixed.

GroupDocs.Comparison for .NET Library and Cloud App

  • Improved comparison of PDFs: switch layers off or on when performing vector-based comparison.
  • Improved detection of added or deleted text.
  • Improved performance.
  • Various bug fixes.

GroupDocs.Conversion for .NET Library and Cloud App

  • Improved performance (using streams for input and output).

GroupDocs Cloud App Platform

  • DWG file format support.
Coming Soon
GroupDocs.Viewer for .NET Library

  • Improved support for mobile devices.
  • Rendering links for email attachments.

GroupDocs.Annotation for .NET Library and Cloud App

  • Tool for underlining text.
  • Measurement tool (ruler).
  • Undo/redo feature.
  • Import/export comments to Microsoft Excel documents.

GroupDocs.Signature Cloud App

  • Tag envelopes, forms and templates to improve organization.

GroupDocs.Comparison for .NET Library and Cloud App

  • Detect moved text.
  • Improved detection of style changes.
  • Compare Microsoft Visio files.
  • Improved comparison of Microsoft PowerPoint files.
From The Library
Integrating GroupDocs.Viewer for Java into a PHP Application
If you are new to GroupDocs.Viewer for Java, and want to integrate it with a PHP web application, this article will have you up and running quickly. It describes what you need, and what you need to do, to add document viewing features to your app. Read the article.
GroupDocs.Viewer for .NET Extension for pimcore
pimcore is an open-source content management and e-commerce platform. We recently developed an extension that lets you add GroupDocs.Viewer for .NET to pimcore websites. Because the extension uses the .NET library and not the Cloud service, you can host it entirely on your own infrastructure. Find out more.
How Can We Help You?
Do you have ideas for what you'd like to see us do in the coming months? Take a minute to tell us.
Integrations and New Cloud API Samples
Product Releases And Updates
GroupDocs.Total for .NET – The latest release of our .NET libraries. GroupDocs.Viewer for Java 2.2.0 – Support for TIFF files and improved watermark handling.
GroupDocs.Viewer for .NET 2.1.2 – Maintenance release. GroupDocs.Annotation for Java 1.4.0 – Import comments and replies on point, area, text and polyline annotations.
GroupDocs.Annotation for .NET 1.3.0 – Various improvements to markup tools and other fixes and enhancements.

Seamlessly Integrate the GroupDocs.Viewer for Java Library into Your DNN Website

GroupDocs.Viewer for Java iconRecently we released a new module which allows developers to seamlessly integrate the Java version of our HTML5 document viewer into DNN websites. Today we're pleased to announce that the module has been approved and officially published on the DNN marketplace.

GroupDocs.Viewer for Java library is an HTML5 document that allows you to embed and display 50+ types of documents on any page within your website. Formats include PDF and Microsoft Word documents, Excel spreadsheets, PowerPoint slides, Visio diagrams and a lot more.

The Java version is the third DNN module we've released for the GroupDocs HTML5 document viewer. Now you can choose between 3 deployment options for the viewer: a downloadable .NET or Java library, which can be hosted on-premises, or a cloud-based on-demand service. For more details on the viewer and available deployment options, please see this page.

Also, please visit the official DNN store for more details on the modules and installation instructions:

> GroupDocs.Viewer for Java Module
> GroupDocs.Viewer for .NET Module
> GroupDocs.Viewer for Cloud Module

PimCore Extension for Easy Integration of the GroupDocs.Viewer for .NET Library Is Now Available for Download

GroupDocs.Viewer for .NET LogoWe're pleased to announce the release of the PimCore extension for the .NET version of our HTML5 document viewer. PimCore developers can now seamlessly integrate the viewer's functionality into their projects. Once installed, you will be able to embed and display almost 50 types of documents, including PDF and Microsoft Office, in your website or web app.

This extension compliments the cloud-based one, which we've released earlier. So, from now you can choose between two deployment options: a cloud on-demand service or the downloadable .NET library. The first one is easier to deploy, but requires documents to be hosted on the GroupDocs servers. If you don't want to expose your content to the Internet and would like to host your documents on-premises, please consider the downloadable .NET version. For more details on the HTML5 document viewer and deployment options, please see this page.

Users who have purchased a license for the GroupDocs.Viewer for .NET library can use the new extension for free. In case you don't have a license, but would like to test the viewer on your PimCore project, please feel free to contact sales for a free 30-day trial.

For more information on the .NET extension, please visit the PimCore marketplace.

Add Security through Custom Caching in the GroupDocs.Viewer for Java Library Version 2.2

GroupDocs.Viewer for Java icon

The GroupDocs.Viewer for Java library is a high-fidelity document viewer, built within HTML5 standards. It allows end-users to view over 45 types of documents on the web without the need to install any third-party software. Here at GroupDocs we always look for new ways to enhance our products with advanced security options. The GroupDocs.Viewer for Java library can be deployed on-premises and allows you to host documents on your private storage. This ensures you have complete control over documents security on the server side. But how to protect your content from unauthorized use when documents are exposed to users?

GroupDocs.Viewer for Java allows you to easily restrict or disable the document printing, downloading and copying options. And in the recently released version 2.2, we've added yet another security layer which allows you to prevent browser cashing of viewed documents (that is, temporary storage of rendered pages).

This option can be enabled with the help of a new parameter called useBrowserCache. In the following article I'd like to provide you with several useful tips about advanced caching strategies you can implement using this parameter, or without it, in case you use an earlier version of the library.

Go to the article >>>

The .NET Version of the GroupDocs HTML5 Document Viewer Can Now Be Seamlessly Integrated into Joomla! CMS

GroupDocs.Viewer for .NET LogoGreetings! We have good news for Joomla! developers. Recently we've released an extension which helps you to easily integrate the .NET version of the GroupDocs HTML5 document viewer into Joomla! websites. And now we are glad to announce that the extension is published and available for download from the official Joomla! marketplace.

Unlike the cloud-based extension released earlier, this one integrates the downloadable .NET version of the GroupDocs.Viewer. It allows you to store and host documents on your (or your clients') servers. There is no need to transfer documents to GroupDocs servers as in the cloud-based version. So, you have complete control over documents security.

The new extension can be used by registered users of the GroupDocs.Viewer for .NET library for free. If you don't have a license for the library and would like to test the extension on your Joomla! website, please feel free to contact our sales for a 30-day trial.

For more details on the extension, please visit Joomla! marketplace.

Integrating GroupDocs.Viewer for Java into a PHP Application

GroupDocs.Viewer for Java library

Recently, we posted a guide describing how to integrate the GroupDocs.Viewer for .NET library into a PHP app. This time I'd like show you how to do the same thing with the Java version of the viewer.

GroupDocs.Viewer is the foundation of most of the other GroupDocs applications. It is a high-fidelity HTML5 document viewer that allows you to display almost 50 types of documents within your own app or website. The viewer doesn't require any client-side installation, allows users to view documents from any HTML5-compliant
browser and comes with a convenient UI for navigating multi-page documents.

If you are developing a PHP app and want to enhance its functionality with a universal document viewer that delivers a great user experience, this article is for you. It gives you a basic sample aimed to show how to integrate the Java version of the GroupDocs.Viewer into a PHP app.

Go to the tutorial >>>

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