Fluent.Ribbon VS Avalonia

https://github.com/fluentribbon/Fluent.Ribbon is another ribbon control for WPF

Avalonia is an open-source UI framework that can run on Windows, macOS, and Linux.

> - If you are working on Linux, you can build and deploy Android apps only

> - You need a valid Visual Studio or IntelliCode subscription

You don't: https://marketplace.visualstudio.com/items?itemName=ms-dotne... (DevKit, which is the licensed one, is completely optional - it gives you VS-style solution explorer. You can already get it with e.g. F#'s Ionide that works for any .NET Code file)

Or https://github.com/razzmatazz/csharp-language-server with either Neovim or Emacs.

> Okay, where's Linux? That's what Mono was originally made for and where Mono really shines.

Regretfully, you have ignored all sibling comments, so here it goes:

Uno: https://platform.uno/docs/articles/get-started-vscode.html?t...

(Uno has more involved setup than Avalonia but has way better mobile targeting, and casual reports indicate smaller memory footprint)

Avalonia: https://avaloniaui.net + https://marketplace.visualstudio.com/items?itemName=Avalonia...

    dotnet new --install Avalonia.Templates

Luckily, for the project of this type, you can use SkiaSharp (which is awesome) or simply implement a rendering back-end that targets OpenGL/Vulkan/DX/Metal. There are rich binding libraries with low/zero overhead to do so or you can just do it directly.

For example, Avalonia implemented Vulkan back-end some time ago, no C or C++ required: https://github.com/AvaloniaUI/Avalonia/pull/12737

You are absolutely not married to Avalonia, MAUI or Uno, but if are targeting desktop, then AvaloniaUI offers great user experience.

This may be your personal experience but it is used successfully and happily by many in a variety of domains way different to "boring OOP back-ends". No popular general purpose language is confined to a single domain like you describe. C# lets you do things like writing a competitive Redis implementation[0], advanced physics engine that beats Jolt[1] or a game engine that does not rely on C++ or C[2], cross-platform applications[3] and so on and so forth. The language itself lets you go from high level FP style approach for business domain modeling to very low-level data crunching that is competitive with systems programming languages.

[0]: https://microsoft.github.io/garnet/docs/benchmarking/results...

[1]: https://github.com/bepu/bepuphysics2

[2]: https://www.stride3d.net

[3]: https://avaloniaui.net

At our research chair (https://mnm-team.org) we used QuIDE (https://quide.eu) quite a lot to try out quantum circuits and teach quantum computing to our students. As many of us were not using Windows that was kind of annoying, because it was only running on Windows.

So one of our students refactored QuIDE for Windows (https://quide.eu) together with us with Avalonia UI (https://avaloniaui.net/) for cross platform use on Linux, macOS and Windows.

I think it's now in a state to be used as replacement for the old version. We're happy about new users and contributors.

Businesses do seem to like AvaloniaUI and Uno.

https://avaloniaui.net/

https://platform.uno/

WPF is not the best example of open source, as some components are still closed source. Though it only runs on Windows, a closed source operating system, so perhaps that is not so important.

https://github.com/dotnet/wpf/issues/2554

That said, there are cross platform, open source .NET UI frameworks out there, including one that is inspired by WPF:

https://avaloniaui.net/

You might also want to look at AvaloniaUI[0] for a cross platform .NET GUI library. It is similar to WPF but much nicer to work with.

[0] https://github.com/AvaloniaUI/Avalonia