1

我已经阅读了这篇很棒的问答，并尝试制作类似的东西。我的模型类是：

public class Person
{
    public int PersonId { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }

    public ICollection<Course> CoursesAttending { get; set; }

    public Person()
    {
        this.CoursesAttending = new List<Course>();
    }
}

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

    public ICollection<Person> Students { get; set; }
}

public class PersonCourse
{
    [Key, Column(Order = 0)]
    public int PersonID { get; set; }
    [Key, Column(Order = 1)]
    public int CourseID { get; set; }

    public virtual Person Student { get; set; }
    public virtual Course StudentCourse { get; set; }

    public int Mark { get; set; }
    public string Comment { get; set; }
}

public class SchoolContext : DbContext
{
    public DbSet<Course> Courses { get; set; }
    public DbSet<Person> People { get; set; }
    public DbSet<PersonCourse> PersonCourseLinks { get; set; }

    public SchoolContext()
        : base("ManyToManyTest")
    {
    }
}

现在，我尝试添加一个新人并将新课程添加到他的课程列表中：

[HttpPost]
    public ActionResult Create(Person person)
    {
        if (ModelState.IsValid)
        {
            Course studentCourse;
            try
            {
                studentCourse = db.Courses.ToList<Course>().First();
            }
            catch
            {
                studentCourse = new Course() { Title = "HTML" };
            }

            person.CoursesAttending.Add(studentCourse);
            db.People.Add(person);
            db.SaveChanges();
            return RedirectToAction("Index");  
        }

        return View(person);
    }

一切顺利，但是当我打开创建的数据库时，我看到 Person 和 Course 类有 2 个链接表 - PersonCourse（带有字段：PersonID、CourseID、Mark、Comment）和 PersonCourse1（带有字段：PersonID、CourseID），并且只有 PersonCourse1 有行（实际上是一行）。为什么会这样？我做错了什么吗？我希望只看到一个链接表 - PersonCourses 表......

4

3 回答 3

1

我希望只看到一个链接表 - PersonCourses 表

然后你必须通过导航属性将PersonCourse实体与Person实体链接起来。CoursesAttending必须对Course实体做同样的事情。

public class Person
{
    public int PersonId { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }

    public ICollection<PersonCourse> CoursesAttending { get; set; }

    public Person()
    {
        this.CoursesAttending = new List<PersonCourse>();
    }
}

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

    public ICollection<PersonCourse> Students { get; set; }
}
于 2012-05-24T13:52:30.067 回答
0

就这样你现在为什么你的代码没有按预期工作：

public class PersonCourse
{
    [Key, Column(Order = 0)]
    public int PersonID { get; set; }
    [Key, Column(Order = 1)]
    public int CourseID { get; set; }

    public virtual Person Person { get; set; } // Follow built in conventions
    public virtual Course Course { get; set; }

    public int Mark { get; set; }
    public string Comment { get; set; }
}

这现在遵循内置的实体框架约定

public int [ClassName][Id] or [Id] //Database Foreign Key column

and

public NavigationProperty [ClassName] // Navigation Property
于 2013-10-08T10:46:59.537 回答
0

为您的动名词表中的外键属性提供外键关联：

public class PersonCourse
{
    [Key, Column(Order = 0)]
    public int PersonID { get; set; }
    [Key, Column(Order = 1)]
    public int CourseID { get; set; }

    [ForeignKey("PersonID")]
    public virtual Person Student { get; set; }

    [ForeignKey("CourseID")]
    public virtual Course StudentCourse { get; set; }

    public int Mark { get; set; }
    public string Comment { get; set; }
}
于 2012-05-24T13:57:46.710 回答