Where can I find Linq ThenInclude method?

Question

I saw some LINQ code examples which contains ThenInclude . Where can I find such method? In external library or other namespace.

I want to use such method for get data for derived, but I cannot find such method or do you know other solution

        return _dbContext.Goals
            .Where(p => p.Owner.Id == userId)
            .Include(p => p.GoalExpectation)
                .ThenInclude<RangeGoalExpectation>(p => p.MinValue)
                .ThenInclude<RangeGoalExpectation>(p => p.MaxValue)
                .ThenInclude<SpecifiedGoalExpectation>(p => p.Value)

Answer 1

然后，Include是Entity Framework Core（EF 7）的一部分。