Microsoft's Connect(); event is taking place today, and the company is making some big announcements. One of which is the fact that Windows Forms, Windows Presentation Framework (WPF) and the Windows XAML Library (WinUI) are all now open source and you can make your contributions to the projects in their respective GitHub repositories.
Microsoft says open-sourcing these technologies helps increase transparency between the product teams and the community, and it should help fans engage with the products. Windows Forms and WinUI are available now, while WPF is only partly available, starting with System.Xaml. More components will be open-sourced over the next few months.
Additionally, Microsoft is releasing the first preview of .NET Core 3.0, bringing capabilities first announced at Build 2018. These include the ability to create desktop apps using Windows Forms, WPF, and XAML Islands to incorporate Fluent Design elements into those apps. Other improvements with .NET Core 3 include support for Entity Framework 6 (EF6), ASP.NET Core 3, EF Core 3 with support for Azure Cosmos DB, and more.
Some of those improvements are also coming to .NET Framework 4.8 next year, as well as better support for higher DPI displays. Of course, .NET Framework doesn't have all the advantages of .NET Core, such as side-by-side deployment, but there are still many people who need it. You can read more about Microsoft's plans for the two platforms here.