OpenSilver 1.1 Improves Silverlight and Telerik Support, Reveals Plans for VB.NET in the Browser

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  • October 11, 2022
  • Cloud PRWire
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Paris, France Oct 11, 2022 ( – Userware announced today that it has released OpenSilver 1.1, a major improvement over last year’s 1.0 release. The update brings it a large step closer to full parity with Microsoft Silverlight.

OpenSilver, the plugin-free, open-source reimplementation of Silverlight, just received several key upgrades:

  • Over 100+ new Silverlight features (see below)
  • Support for additional third-party libraries, including Telerik UI
  • 3x improvement in performance over v1.0
  • What’s next: VB.NET support coming soon

Over 100+ New Silverlight Features

Moving code from Silverlight to OpenSilver is made easier with support for over 100 additional Silverlight APIs. Developers can now reuse more than 99% of their Silverlight application’s code. New features include:

  • New DataGrid: based on the original code from Microsoft, the new DataGrid is feature-packed and offers pixel-perfect backward compatibility
  • Silverlight Toolkit: most controls are now supported in OpenSilver, including DataForm, Accordion, AutoCompleteBox, DataPager, LineSeries…
  • Improved layout system: OpenSilver now supports the “Measure” and “Arrange” Silverlight APIs for creating custom panels and layouts

Applications migrated from Silverlight now render almost identically, at pixel-perfect level,” says Giovanni Albani, CEO of Userware, the company behind OpenSilver. “Some clients have even asked us to make changes to their code on purpose, just to distinguish the migrated version from the original one.

Support for Additional Third-Party Libraries, including Telerik UI

Last year’s 1.0 release of OpenSilver already supported most of the popular Silverlight libraries, including RIA Services, PRISM, MEF, Unity, OData, MVVM Light, and Newtonsoft.

The new 1.1 release adds support for even more libraries, including:

  • SignalR
  • Caliburn.Micro
  • PostSharp
  • Blacklight Controls
  • Google Protobuf
  • Reactive Extensions
  • MS Expression Interaction/Behaviors
  • Microsoft Enterprise Library

Support for the Telerik UI suite of controls has also been improved. Thanks to better support for low-level Silverlight APIs, the full source code of “Telerik UI for Silverlight” can now be compiled and run with OpenSilver.

Most Telerik UI components now work flawlessly, including:

  • RadGridView
  • RadRibbon
  • RadScheduleView
  • RadTreeListView
  • RadChart
  • and dozens of other controls

Performance Improvements

New features like Virtualization, .NET 7 support, and several major optimizations have led to a significant improvement in overall performance.

On average, we improved performance by up to 3 times,” says Albani. “We’ve observed this while porting Silverlight business apps to OpenSilver for our clients. Some portions of their applications now run even faster in OpenSilver than in their original Silverlight version.

VB.NET Support Coming Next

With this release, Userware has been working on laying the groundwork for an upcoming innovation: supporting VB.NET in the browser.

This will make OpenSilver the only technology out there that supports VB.NET and XAML to build web apps“, says Albani. “It will throw a lifeline to the huge number of Visual Basic developers that are out there, and that is sad to see their favorite programming language being progressively abandoned. As we are flooded with requests for assistance to migrate VB.NET Silverlight applications, we believe that this feature will find a lot of interest in the Microsoft developer community.

VB.NET support is expected to come in OpenSilver 2.0, planned to be released in early 2023.


OpenSilver 1.1 is available for download at:
Source code:
Full changelog:


About OpenSilver

OpenSilver is a modern, plugin-free, open-source reimplementation of Silverlight, capable of running large, complex legacy applications, as well as newly written C# and XAML applications.

It provides a 3 to 5 times faster alternative to rewriting Silverlight applications, letting developers leverage their .NET skills and focus on new improvements instead. Over 99% of Silverlight code can be ported to OpenSilver without any code changes. Migrated applications preserve the look and functionality of the original ones, and can run securely on all browsers without requiring a plugin.

The project is hosted publicly on GitHub and is actively developed by a large team of full-time developers, funded by Userware – which provides support and migration services -, and corporations of all sizes investing in the technology to maintain their line-of-business applications. The development of OpenSilver was motivated by the team’s strong belief that developers should not be compelled to rewrite existing applications because of a change in the underlying stack.

OpenSilver applications run on every modern browser, across all platforms, including iOS, Android, Windows, MacOS, and Linux.

About Userware

Userware is a software company founded in 2007 by two experts in Microsoft technologies. It is based in Paris, France, and has a portfolio of products with more than 25,000 customers in over 75 countries. Specializing in Microsoft technologies and developer tools, the company started the OpenSilver project in 2014 and has been constantly improving it for over 8 years with a dedicated team of developers and an active community of contributors.

OUR VISION: “We are .NET developers who believe that Silverlight was the best platform ever for developing line-of-business (LOB) applications. We were sad to see Silverlight die due to the lack of support for plug-ins in modern browsers, so we wanted to reimplement it using modern, open, and standards-based technologies. We aim at making it even more powerful than before, for developers to have the tools to build amazing products that can change the world.”

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Source :Userware SARL

This article was originally published by IssueWire. Read the original article here.

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