We’re excited to release .NET 5.0 today and for you to start using it. It’s a major release — including C# 9 and F# 5 — with a broad set of new features and compelling improvements. It’s already in active use by teams at Microsoft and other companies, in production and for performance testing. Those teams are showing us great results that demonstrate performance gains and/or opportunities to reduce hosting costs for their web applications.
ASP.NET Core, EF Core, C# 9, and F# 5 are also released today. You can download .NET 5.0 for Windows, macOS, and Linux on both x86 and ARM.
Does it allow making GUI apps on Linux?
I believe so — now that .NET Core and the Common Language Runtime have been officially supported on Linux for a few years, FWIU GUI apps on Linux have been possible for a while. Don’t know what GUI toolkits are supported though — GTK# is the go-to toolkit, I believe, since Miguel de Icaza and the Mono team have been working on it for ages.
Maui is the future here will be in .NET 6 next year. WPF will work with WINE, maybe winforms would work too but that’s terrible.
https://devblogs.microsoft.com/dotnet/introducing-net-multi-platform-app-ui/
.NET Core and .NET 5 support Windows Forms only on Windows:
https://docs.microsoft.com/en-us/dotnet/desktop/winforms/migration/?view=netdesktop-5.0
Same story for WPF, apparently:
https://docs.microsoft.com/en-us/answers/questions/19216/wpf-in-linux.html
“.NET Core and .NET 5 support Windows Forms only on Windows:”
So making multi platform GUI apps in .NET is still not here.
Winforms does not support Linux and maybe never will. But as kzagoris points out, there is the cross-platform Maui GUI framework based on Xamarin Forms (which I’ve never used), scheduled to ship with .NET 6 a year from now; previews will be available before then. Linux support hasn’t be advertised though.
You can develop GUI apps for a long time using a cross-platform GUI (for example, GTK#). Next year, we will have the Maui, which is an upgraded Xamarin.Forms toolkit. Of course, there is the Uno platform way :
https://platform.uno/
which recently port the Windows calculator as a showcase
https://www.omgubuntu.co.uk/2020/10/install-windows-calculator-ubuntu
I feel a bit sorry for authors like this guy:
https://www.manning.com/books/asp-net-core-in-action-second-edition
He probably had a bunch of stuff written about ASP.NET Core 3.1 that either has to be rewritten, or supplemented with material on how things now work in .NET 5. And based on experience with .NET Core, there will be a whole bunch of changes; there are lots of fads and fashions in this area, plus the unification of the .NET stack brings in scads of Microsoft politics and legacy architecture. OTOH if the author and his editor decide not to add the supplement, potential buyers will be unhappy.