May 21, 2020 07:21 AM|dean4if|LINK
Thanks for your response Bruce. I had tried several ways of setting my Class Library up, including manually editing the csproj file, updating the version in the Property pages and creating a new project from scratch.
In each of these cases, I had to add a references to Microsoft.AspNetCore.Mvc.TagHelpers, Microsoft.AspNetCore.Mvc.ViewFeatures and Microsoft.AspNetCore.Razor ... All of these were Version="2.2.0"
These all failed with the same problem reported in my original post.