I have this sample code:
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using Models;
namespace MySampleNamespace
{
Depending on your .Net version you are using. Microsoft.EntityFrameworkCore.Tools.DotNet
only supports .NetStandard >= 2.0.
If your .Net version is 4.6.1, update Microsoft.EntityFrameworkCore
to 2.0.0-preview1-final, along with related EntityFramework DLLs, then close Visual Studio 2017 and re-open.