Microsoft Open Sources WPF, Windows Forms and Windows UI XAML Library

The moves were announced at the Microsoft Connect (); 2018 conference, where the company also unveiled .NET Core 3 Preview 1.

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Microsoft is continuing its recent efforts to share some of its code as open source by announcing that its Windows Presentation Framework (WPF), Windows Forms and Windows UI XAML Library will now have their code contributed as open-source projects.

Announced at the company's Windows Connect (); 2018 developers conference, the moves are being made to provide transparency between the product team and the community, help democratize Windows development, and enable the community to engage and contribute to the code, wrote Kevin Gallo, corporate vice president of the Windows Developer Platform in a Dec. 4 post on the Windows Blog.

Also unveiled at the conference was Microsoft’s .NET Core 3 Preview 1 code, which adds support for building apps using WPF, Windows Forms and XAML Islands.

"Our three, popular Windows UX frameworks are ready for your contributions on GitHub: WPF, Windows Forms, and WinUI," Gallo wrote in his post. "We look forward to your contributions. You can get started with Windows Forms and WinUI now. WPF is starting with System.Xaml, with more to come over the following months."

WPF, a UI framework for building Windows desktop applications, supports a broad set of application development features including an application model, resources, controls, graphics, layout, data binding and documents. WPF uses the Extensible Application Markup Language (XAML) to provide a declarative model for application programming, according to Microsoft.

Windows Forms, also called WinForms, is another UI framework for building Windows desktop applications. It is used as a .NET wrapper over Windows user interface libraries, such as User32 and GDI+, and also includes controls and other unique functions. It allows developers to create desktop applications based on the visual designer provided in Visual Studio, with drag-and-drop of visual controls and other capabilities.

The Windows UI Library is a set of open-source Microsoft UI controls and features for the Windows UWP platform, which gives developers the tools to build fluent design experiences for Windows. WinUI can be used in any Windows 10 UWP XAML app, or in a Xamarin.Forms app running on Windows 10 using native view embedding.

The new .NET Core 3 Preview 1 release allows users to run multiple instances of .NET Core 3.0 side-by-side on the same computer so they can update WPF and Windows Forms apps to a new version of .NET without updating the entire operating system, according to Microsoft. It also enables developers to use modern controls and Fluent styling from the WinUI XAML Library via XAML Islands from .NET Core 3.0 apps.

The .NET Core 3 Preview 1 code is available for download immediately.

The next version of the .NET Framework, .NET Framework 4.8, will include new controls that use the latest browser and media players in Windows 10, support the latest standards and will provide access to WinUI via XAML Islands for WPF and Windows Forms apps.