如何获取C＃中另一个对象内的对象计数？

Question

应用程序类具有Applicant对象：

  public class Application
 { 
  public virtual ICollection<Applicant.Applicant> Applicants { get; set; }
 ...
 }

申请人类将Employee对象作为集合：

 public class Applicant
{
   public virtual ICollection<Employment> Employments { get; set; }
 } 

如何以这种方法获得就业人数：

  public void InsertApplication(Application application)

Answer 1

您可以使用application.SelectMany(a=>a.Applicants.SelectMany(x=>x.Employments)).Count()

Answer 2

使用Count property可以检索Default Web Site Applicant次{...}

Employment

applicant.Employments.Count Application个Employment计数是Applicant Employment个application.Applicants.Sum(applicant => applicant.Employments.Count); 点数的sum ...

heroku run rake db:schema:dump
heroku restart