Why does the .NetCore Class Library reference .NetStandard?

In VS2015 > New Project > .Net Core, there is a template for "Class Library (.NET Core)"

It wasn't until I tried to reference this library in a .NET Core Web API program, that I realized that the Class Library template is referencing .NETStandard v1.6. And my .NET Core API porject won't take it as a reference. I was trying to avoid building the library as a nuget package.

Any ideas on why a Core template isn't referencing core? Any ideas on quick workarounds?

Update: Opened a new "Class Library (.NET Core)", before first build I changed frameworks in project.json to

"netcoreapp1.0": { "imports": [ "dotnet5.6", "portable-net45+win8" ]

Then I created, in a different VS instance, a new "ASP.NET Core Web Application (.NET Core)".

I tried to add a reference to the .dll file for the new class library, now in a netcoreapp1.0 folder and I still get the same error:

.NET Core Projects only support referencing .NET framework assemblies in this release.

Solution

How to fix your problem

I was trying to avoid building the library as a nuget package.

Any ideas on why a Core template isn't referencing core? Any ideas on quick workarounds?

When you try to add the .dll as a reference for the API, your error message should say somewhere that you need to create a package in order to use that class library. It is described in the documentation.

However if you do not want to bother to make a package, for example if your class library is used now only in your API project, the easiest way is to build your class library as a Project of your Solution where the API lives. To do so, copy-paste your code in the Solution folder and include it as a project.

Some explanations about the version and frameworks

The Core template (I guess you are talking about the .NET Core API) should create a project.json with

  "frameworks": {
    "netcoreapp1.0": {
         "imports": [
             "dotnet5.6",
             "portable-net45+win8"
       ]
    }
  }

Let's see what the lines are responsible for:

netcoreapp1.0 under frameworks means your API is targeting the framework .NET Core 1.0. That version of the .NET Core framework implements the .NET Standard 1.6 (the list here) Good thing: your Class library also use this .NET Standard 1.6. Knowing the .NET Standard 1.6 that your Class library is using make you able to choose what version of .NET Core/Xamarin/.NET Framework you can use when you later want to develop a Web app/Mobile app/Windows software for example
imports lists other frameworks/version of packages that your application can use
According to this link dotnet5.6 and portable-net45+win8 are deprecated and a netstandard version should be used instead. dotnet5.6 is still mysterious for me. portable-net45+win8 is equivalent to netstandard1.0. If you let it it means that your application can use package using .NET Standard 1.0. This can be a problem because .NET Core 1.0 starts with .NET Standard 1.6 so I would actually delete those two lines.

That being said, I am more than welcome for comments!