Problems adding links to netstandard 2.0

Question

I changed the Asp.Net Core 1.1 application to Core 2.0

This went pretty well, but after I updated my nuget packages and I get this error everywhere

The type 'xxx' is defined in an assembly that is not referenced. You must add a reference to the assembly 'netstandard, Version = 2.0.0.0, Culture = neutral, PublicKeyToken = cc7b13ffcd2ddd51'.

When I click the button to add an assembly, nothing happens. I tried to repair and restore my packages several times, but this will not work

Answer 1

I think you are having a problem linking to an old version of NETStandard in your class library. Just make sure you remove the NETStandard link from all csproj files in the solution.