使用EF生成的两个外键

public class Student
{
    public int StudentId { get; set; }
    public string Name { get; set; }

    // 导航属性
    public ICollection<Enrollment> Enrollments { get; set; }
}

public class Course
{
    public int CourseId { get; set; }
    public string Title { get; set; }

    // 导航属性
    public ICollection<Enrollment> Enrollments { get; set; }
}

public class Enrollment
{
    public int EnrollmentId { get; set; }
    public int CourseId { get; set; }
    public int StudentId { get; set; }
    public Grade? Grade { get; set; }

    // 导航属性
    public Course Course { get; set; }
    public Student Student { get; set; }
}

public enum Grade
{
    A, B, C, D, F
}

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Enrollment>()
        .HasKey(e => new { e.StudentId, e.CourseId });

    modelBuilder.Entity<Enrollment>()
        .HasOne(e => e.Student)
        .WithMany(s => s.Enrollments)
        .HasForeignKey(e => e.StudentId);

    modelBuilder.Entity<Enrollment>()
        .HasOne(e => e.Course)
        .WithMany(c => c.Enrollments)
        .HasForeignKey(e => e.CourseId);
}

public virtual ICollection<Enrollment> Enrollments { get; set; }

var studentsWithCourses = context.Students.Include(s => s.Enrollments).ThenInclude(e => e.Course);