查询，如何让项目NUMER在特定的类

Question

我想出这个：

[NotMapped] 
    public int ThreadsInBoard 
    { 
     get 
     { 
      ForumContextContainer ctx = new ForumContextContainer(); 
      int thr = (from p in ctx.BoardSet 
         from x in ctx.ThreadSet 
         where p.BoardID == x.Board.BoardID 
         select p).Count(); 
     } 
    } 

我想要做的是线程，是在特定的板的数量。 此查询实际上返回数据库中每个可能的线程的计数并分配它。 下面是参与类

public partial class Board 
{ 
    public int BoardID { get; set; } 
    public string Name { get; set; } 
    public string Description { get; set; } 
    public bool IsVisibleToGuests { get; set; } 
    public bool IsLocked { get; set; } 

    public Forum Forum { get; set; } 
    public ICollection<Thread> Thread { get; set; } 
} 

    public partial class Thread 
{ 
    public int ThreadID { get; set; } 

    public User User { get; set; } 
    public ICollection<Post> Post { get; set; } 
    public Board Board { get; set; } 
    public ICollection<Subscription> Subscription { get; set; } 
    public ICollection<Poll> Poll { get; set; } 
} 

Answer 1

[NotMapped] 
    public int ThreadsInBoard 
    { 
     get 
     { 
      ForumContextContainer ctx = new ForumContextContainer(); 
      int thr = ctx.ThreadSet.Count(p => p.BoardID == this.BoardID); 
     } 
    } 

假设这个类有板卡ID属性