Migrating Microsoft.Net Framework assemblies to .Net Core framework

Implementing existing .Net Framework libraries as shared .Net Standard libraries inevitably requires a migration, similar to porting to .Net Core.

Microsoft’s API Port tool can tell you how much work this will involve. It is a command line tool that gives you a detailed breakdown of the types and members that will cause compatibility issues.

In some cases, they will require a particular version of the .Net Standard, while others will not be supported at all.

Microsoft think that more than 60% of the most commonly used .Net Framework packages on NuGet will be compatible with .Net Standard via the shim. This should make it easier to make a commitment to .Net Core as many legacy .Net Framework libraries will be accessible to via .Net Standard.

Windows Forms and WPF in particular will forever remain in the .Net Framework as Windows Universal applications have become the new UI creed. Anything that relies on platform-specific features will also be excluded.

Multi-targeting can help to widen the reach of shared libraries. This allows you to compile a single project natively for both .Net Standard and your preferred version of the .Net Framework, though it does come at a cost of having to manage multiple sets of compiled output.