Question

我想从GroupBook Class返回，他们拥有相同组ID的一套书......

我在这些表之间有这种关系：

public class GroupBook
{
    [Key]
    public int Id { get; set; }

    [Required]
    public int Book_Id { get; set; }

    [Required]
    public string User_Id { get; set; }

    [Required]
    public int Group_id { get; set; }

    public virtual AspNetUser AspNetUser { get; set; }

    public virtual Book Book { get; set; }

    public virtual Group Group { get; set; }

}

 public partial class Group
{
    public Group()
    {

        GroupBooks = new HashSet<GroupBook>();
    }
    [Key]
    public int Group_id { get; set; }

    [Required]

    public string Group_name { get; set; }

    public string Group_description { get; set; }

    public string UrlSlug { get; set; }

    public int state { get; set; }

    [Required]        
    public string User_Id { get; set; }

    public virtual AspNetUser AspNetUser { get; set; }

    public virtual ICollection<GroupBook> GroupBooks { get; set; }

}

也是我的书桌：

public partial class Book
{
    public Book()
    {

        GroupBooks = new HashSet<GroupBook>();
    }
    [Key]
    public int Book_id { get; set; }
    [Required]
    [StringLength(128)]
    public string User_ID { get; set; }
    public string UrlSlug { get; set; }
    [Required]
    public string Book_name { get; set; }
    public string Book_Description { get; set; }
    public virtual ICollection<GroupBook> GroupBooks { get; set; }
    public virtual AspNetUser AspNetUser { get; set; }
}

这是我的Vm：

public class GroupVm
{
      public List<Book> Book { set; get; }


}

我想在VM这套书中返回：

public ActionResult Index(int? Group_id)
    {            
        Vm=db.books.where(//What to add here to return set of books that == the group id I will send via method)
    }

如上例所示，我只想返回与同一group_id存在的一套书，请该怎么做？

Answer 1

将DbSet<GroupBook> GroupBooks添加到DbContext。

然后做点什么：

var vm = new GroupVm();
vm.Book = db.GroupBooks.Where(g => g.Group_id == Group_id).Select(g => g.Book).ToList();

如何从多对多结果中返回VM？

1 个答案: