OpenSilver: an open source reimplementation of Silverlight


The OpenSilver project was presentedwhich is intended to create an open implementation of the Silverlight platform, whose development was discontinued by Microsoft in 2011 and maintenance will last until 2021.

Silverlight is a technology that enables the development of rich web applications (RIA) in a vector rendering engine that will no longer be supported starting next year. userware, a software company founded by two Microsoft technology experts announced the launch of OpenSilver, an open source reimplementation of Silverlight that works in all browsers through WebAssembly.

As is the case with Adobe Flash, Silverlight its development is being minimized in favor of the use of standard web-based technologies. At one point, the open implementation of Silverligh “Moonlight” was already being developed on the basis of Mono, but its development was halted due to the lack of demand for technology by users.

The OpenSilver project made another attempt to revive Silverlight technology, which allows you to create interactive web applications using C #, XAML, and .NET. One One of the main objectives of the project is to extend the useful life of Silverlight applications existing in the terms of end of platform support and end of browser support for add-ons.

However, proponents of .NET and C # technology can also use OpenSilver to create new programs.

In a press release from Userware, Giovanni Albani, CEO of the company, said:

"With most browsers no longer supporting plug-ins like Microsoft Silverlight, .NET developers have been left without a way to build rich client-side applications that run in the browser." "But with the advent of WebAssembly, an open standard that is now supported by most desktop and mobile browsers, this is no longer the case."

The OpenSilver framework is based on the Mono open projects code (mono-wasm) and Microsoft Blazor (part of ASP.NET Core) and WebAssembly is used for execution in the browser build of applications in intermediate code.

OpenSilver is being developed together with the CSHTML5 project, which allows C # / XAML applications to run in a browser by compiling it into JavaScript. OpenSilver uses the existing CSHTML5 code base, replacing the compilation components in JavaScript with WebAssembly.

OpenSilver applications are compatible with all browsers that support Web Assembly, which includes the main browsers (Edge, Chrome, Firefox, Safari ...), on all major platforms (Windows, macOS, iOS, Android, Linux, ChromeOS ...), without users having to install a plug-in, according to Userware.

For existing Silverlight applications, they must be recompiled with OpenSilver in order to work in these browsers.

“We are .NET developers who believe that Silverlight was the best platform for developing line of business (LOB) applications. We are sad to see Silverlight disappear due to lack of plugin support in modern browsers.

So we want to save it by re-implementing it with modern, open, standards-based technologies. We want to make it even more incredible than before, so that developers have the tools to create incredible products that can change the world ”, is the vision expressed by the team.

In its current form, support is provided for approximately 60% of Silverlight programming interfaces More popular.

This year, it is planned to add support for Open RIA and Telerik UI services, as well as synchronize with the new Blazor and Mono project code base for WebAssembly, which is expected to support proactive compilation (Ahead-of-Time, AOT). , which will help improve performance by testing up to 30 times.

According to the press release, migrating the Silverlight code to OpenSilver offers multiple benefits, including cost reduction. According to Userware, it can be 3 to 5 times cheaper to migrate a Silverlight application to OpenSilver than to rewrite it from scratch using another technology.

The project code is distributed under the MIT license.


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