I develop a C# class library (.NET Framework 4.7.2) that uses the NuGet package Microsoft.Office.Interop.Outlook. After installing the package with the NuGet Package Manager, the produced assembly has no references to Microsoft.Office.Interop.Outlook. Instead, the Outlook symbols are copied into my assembly. If I now migrate packages.config to PackageReference, the produced assembly references Microsoft.Office.Interop.Outlook and the Outlook symbols disappear from my assembly.
I confirmed this by looking at the ILSpy output for a small demo project that uses OlAccountType. Here is the output using packages.config:
And here is the output using PackageReference:
Why does the same package behave differently here?
I like the old behavior, because this way, my DLL does not depend on the Outlook DLL. How can I use PackageReference and still get the old behavior?