There is an article published in April 2017 on how to support both runtimes from the same solution:
https://learn.microsoft.com/en-us/dotnet/core/porting/project-structure
It boils down to 2 methods:
- Having both frameworks configured in the same project (e.g. *.csproj):
Replace existing projects with a multi-targeted .NET Core project.
- Having a separate project for each framework:
Keep existing projects and create a .NET Core project.
We are actively discussing which way to go in pythonnet, since the project supports .NET Framework on Windows and Mono on Linux/OSX. Now we are adding cross-platform pythonnet support:
https://github.com/pythonnet/pythonnet/pull/518