How to call Windows Runtime Apis without setting the dotnet TargetFramework to net8-windows.X?

I want to create a dotnet library that supports both linux and windows. The library detects on which OS it is running and executes the respective implementation. For the windows implementation, I need windows apis, which I could get by setting my TargetFramework to (for example) net8.0-windows10.0.19041.0 .

However, I really don't want/cannot change my TargetFramework. It has to stay on net8.0 and net8.0 only. Multiple TargetFrameworks are also not an option for me.

Question: How can I access Windows Runtime Apis while staying on net8.0?

The only available information online always tells me to change my Target Framework Monikor to net8.0-windows.X but, as stated above this is no option for me. There also is the Microsoft.Windows.SDK.NET.Ref nuget package which I tried to include. However, when building I get the error NU1213:

error NU1213: The package Microsoft.Windows.SDK.NET.Ref 10.0.26100.57 has a package type DotnetPlatform that is incompatible with this project.

My conclusion reading into the error leads me to believe that the nuget has a custom package type which cannot be installed by nuget. My knowledge and the information online is, however, quite limited so maybe there is a different reason.

What works so far

After a lot of testing, I managed to get something working, but it feels very hacky.

The main idea is, to load the windows assembly dynamically at runtime. I can test for the executing OS and then only load and instantiate the assembly if we are on windows.

My overall structure looks like this (omitting .csproj files):

├── BaseProject - TargetFramework: net8.0
│   └── IMyInterface.cs
├── ConsoleProject - TargetFramework: net8.0
│   ├── Microsoft.Windows.SDK.NET.dll
│   └── Programm.cs
└── WindowsProject - TargetFramework: net8.0-windows10.0.19041.0
    └── MyClass.cs (implements IMyInterface)

In my BaseProject, I have defined an Interface that is implemented by class MyClass of the WindowsProject.

The ConsoleProject Program.cs looks like similar to this:

var assembly = Assembly.LoadFile("windowsAssembly");

var windowsClassType = assembly.GetType("MyClass");

IMyInterface windowsClass = Activator.CreateInstance(windowsClassType) as IMyInterface;

await windowsClass.SomeMethodAsync().ConfigureAwait(false);

In my small test, the SomeMethodAsync methods accesses the Windows Apis by getting the default Bluetooth adapter.

This setup does not yet fully work, because when SomeMethodAsync is called, I get a runtime error:

System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types. Could not load file or assembly 'Microsoft.Windows.SDK.NET, Version=10.0.19041.38, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. The system cannot find the file specified.

When I build/publish WindowsProject, the Microsoft.Windows.SDK.NET assembly does not seem to be included in the WindowsProject.dll?!

To get it to run, I extracted the .dlls from the Microsoft.Windows.SDK.NET.Ref nuget and manually added them in the ConsoleProject .csproj.

Now it works (but at what cost 😶).