小编Kmr*_*Raz的帖子

我有一个模型类

public class Student
{
    public int StudentId { get; set; }
    public string StudentName { get; set; }
    public ICollection<SelectListItem> CourseList { get; set; }
}

和

public class StudentContext : DbContext
{
    public DbSet<Student> Students { get; set; }
}

我试着用它作为

List<Student> sList =  db.Students.ToList();

我得到了以下错误

\tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'SelectListItem' has no key defined. Define     the key for this EntityType.
\tSystem.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'SelectListItems' is based on type   'SelectListItem' that has no keys defined.

请告诉我在哪里做错了.