Custom Actions with .Net 7

[mjanulaitis]

I am trying to create a custom action using .Net 7. I don't see any documentation for .Net Core custom actions. I stumbled upon WixToolset.Dtf.WindowsInstaller in NuGet and was able to get the [CustomAction] attribute to be recognized however when I build I get the following error:

EXEC : error : Invalid argument: WixToolset.Dtf.WindowsInstaller.dll must be included in the list of support files. If using the MSBuild targets, make sure the assembly reference has the Private (Copy Local) flag set.

Is this the correct package to reference? If so, what changes do I need to make to get this to work?

[barnson]

DTF only supports .NET Framework-based custom actions (for now).

[HungryDoctor]

@mjanulaitis, there is a WA for the issue. You can use <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>. But the real issue is that WixToolset.Dtf.MakeSfxCA.exe is built to net472 and it won't be able to load net7.0 libraries. Even if you put full .net7.0 runtime to the exe file.
I tried to build MakeSfxCA to net6.0, but since there are assembly loading changes (Assembly.ReflectionOnlyLoad is deprecated), it won't work so simple. If Assembly.ReflectionOnlyLoad is replaced with Assembly.Load it still won't work out of the box because of .net assembly loading mechanism is different.
@barnson, is there any workaround for targeting .net6.0 custom actions? If there is no WA, will this feature be available in v5?

[HungryDoctor]

@barnson, are there any possible issues besides reflection? If no, I can try to rewrite the reflection loading part with MetadataLoadContext.

[barnson]

It requires hosting .NET Core, which is very different than hosting .NET Framework.

[HungryDoctor]

I see. Hopefully, the feature will be available in the next releases

[barnson]

Only if someone implements it.