DRNJ

The Problem

API Versioning was added to a Microsoft C# Web API project .NET Core.

[ApiVersion("2.1")]
public class MyController: ApiController
{
}

The Swagger page for the API then did not list the API endpoints

The Solution

Simply add the [ApiController] attribute to the class

[ApiVersion("2.1")]
[ApiController]
public class MyController: ApiController
{
}