.NET Core is Microsoft’s new incarnation of .NET, where many things have been changed to be able to accommodate future needs for (primarily server side) application development. This is also the biggest change ever in the .NET world that is not backwards compatible!
For a long time we have had the ability to take an old .NET 2.0 DLL and plop it down next to our other DLLs, and then we would be able to use it right away. Because .NET Core is such a huge change (i.e. it uses a radically re-engineered runtime), that is no longer possible.
This puts a big burden on library developers (e.g. like me 🙂 ) who want to be prepared for the future, while supporting all of the old stuff still.
The good news is that with Visual Studio 2017 and the new CSPROJ format, it has actually become pretty straightforward to write libraries that target multiple frameworks by leveraging the <TargetFrameworks> element in the CSPROJ file (note the plural ‘s’ in there – when you create a new project, there is a <TargetFramework> element, but you need to add an ‘s’ if you put several targets in there).
By the power of open source and a persevering Rebus contributor, beta versions of Rebus 4 have now been released, targeting .NET 4.5 as always as well as .NETStandard 1.6 (which is .NET Core 1.0)
I am now in the process of porting all of the 40+ Rebus projects that it makes sense to port. You can follow the progress here. If you feel like messing a bit with .NET Core and becoming a Rebus contributor, feel free to get in touch and then we’ll figure out how you can help.
Exciting times ahead! 🙂