How can Avalonia UI use .NET 9 to create nuget packages?

[4Darmygeometry]

.NET 9 had been released and support AI interface, LoongArch ABI2.0 and RISC-V 64 architecture.

[rabbitism]

You can use net8 package in net9 project.

[4Darmygeometry]

You can use net8 package in net9 project.

Although Avalonia UI can be used in .NET 9, since it is itself written in .NET 8, it still requires the apphost of .NET 8. However, the apphost of .NET 8 is only supported by the old world (LoongArch64 ABI 1.0), which inevitably requires pulling the Loongson source (https://nuget.loongnix.cn/). Upgrading Avalonia UI to .NET 9 for compilation can pull the apphost of .NET 9, which is supported by the new world (LoongArch64 ABI 2.0).
https://areweloongyet.com/

[thevortexcloud]

since it is itself written in .NET 8

It actually targets .NET Standard 2.0. Which means it will work on .NET Framework as well (although it's not as well supported). Which means it should work with Mono, but I have never tried it. But I can confirm it worked fine the last time I tried it with 4.8 on Windows.

[maxkatz6]

it still requires the apphost of .NET 8

It doesn't. You can use .NET 9 TFM (TargetFramework=net9.0) with Avalonia. Or even .NET 10 previews.

[thevortexcloud]

As far as I am aware, RISC-V support is still a work in progress? It's not even supported by Microsoft. All the work is being done by Samsung.

Anyway, Avalonia itself has no restrictions on using .NET 9 with a third party package.

[4Darmygeometry]

As far as I am aware, RISC-V support is still a work in progress? It's not even supported by Microsoft. All the work is being done by Samsung.

Anyway, Avalonia itself has no restrictions on using .NET 9 with a third party package.

https://learn.microsoft.com/en-us/dotnet/api/system.runtime.interopservices.architecture?view=net-9.0
In Architecture Enum from .NET 9 document, RISC-V 64 has been support.
https://nuget.info/packages/SQLitePCLRaw.lib.e_sqlite3/2.1.11 has the nuget packages of linux-riscv64 and linux-musl-riscv64.
for ref
ericsink/cb@fe4e425
ericsink/SQLitePCL.raw@685942a

[thevortexcloud]

There are no .NET RISC-V binaries available to download though.

https://dotnet.microsoft.com/en-us/download/dotnet/9.0

RISC-V only started development a couple years ago.

dotnet/runtime#84834

I don't think all the changes have even been merged. Last I heard was some things worked and some things don't.

In Architecture Enum from .NET 9 document, RISC-V 64 has been support.

That enum actually only makes sense in the context of Mono. Which supports far more platforms than Coreclr does. Mono however is not the modern .NET runtime and is only sort of still supported. There are actually now two main versions of Mono as well.

https://www.mono-project.com/
https://www.mono-project.com/docs/about-mono/supported-platforms/

Mono has also only really officially supported up to .NET Framework 4.8. My understanding though is Microsoft's fork has some backported features for mobile devices, as coreclr was never ported to those platforms.

tl;dr You are not running .NET 9 with Mono on a desktop.