Question

我有一个Application Object，其中包含Applicant对象。申请人对象有雇员对象，其中包含有关就业的所有信息（姓名，地址，......），这可以是0或2,3,4，......我如何获得1个申请的Emp of Count？所以在这种情况下，它必须返回4.但我的代码返回2，因为它返回每个申请人的计数而不是申请。

这是我的代码：

 public void InsertApplication(Application application)
    {
        if (application.Applicants != null)
        {
            foreach (var item in application.Applicants)
            {
                if (item.Employments != null)
                {
                    application.NumberOfEmployments = item.Employments.Count();
                }
            }
        }
        creditApplicationsContext.Applications.Add(application);
    }

这是应用程序对象：

  public class Application
    {
      public int Id { get; set; }
      public virtual ICollection<Applicant.Applicant> Applicants { get; set;    }
      public int? NumberOfEmployments { get; set; }

这是申请人对象：

 public class Applicant
{

    public int Id { get; set; }
    public virtual ICollection<Employment> Employments { get; set; }
      ....
     }

这是就业对象：

  public class Employment
  {

    public int Id { get; set; }
    public string EmployerName { get; set; }
    public string EmployerPhoneNumber { get; set; }
    public Applicant Applicant { get; set; } 
     .....
    }

Answer 1

如果我正确理解您的结构，您应该能够使用相当简单的SelectMany和Count：

application.Applicants.SelectMany(a => a.Employments).Count();

Answer 2

嗯，你几乎就在那里，问题是你要替换每个子节点的值，而不是添加它。

更改为：

public void InsertApplication(Application application)
{
    application.NumberOfEmployments = 0;

    if (application.Applicants != null)
    {
        foreach (var item in application.Applicants)
        {
            if (item.Employments != null)
            {
                application.NumberOfEmployments += item.Employments.Count();
            }
        }
    }
    creditApplicationsContext.Applications.Add(application);
}

Answer 3

SelectMany可以提供帮助：

application.Applicants.SelectMany(x => x.Employments).Count();

Answer 4

您可以添加一个方法来获取应用程序数量并使用SelectMany

 public class Application
    {
        public int Id { get; set; }
        public virtual ICollection<Applicant> Applicants { get; set; }
        public int? NumberOfEmployments { get; set; }

        public int GetNumberOfApplications()
        {
            return this.Applicants.SelectMany(x => x.Employments).Count();
        }
    }

Answer 5

application.NumberOfEmployments =
    application.Sum(app1 => app1.Applicants.Sum(app2 => app2.Employments.Count()));

Answer 6

要获得代码的总数，请在代码中考虑此更改：

public void InsertApplication(Application application)
{
    if (application.Applicants != null)
    {
        foreach (var item in application.Applicants)
        {
            if (item.Employments != null)
            {
                application.NumberOfEmployments += item.Employments.Count();
            }
        }
    }
    creditApplicationsContext.Applications.Add(application);
}

通过这种方式，您可以获得就业总数。我认为你的代码返回2是因为是最后一个应用程序的就业数量。

C＃中孩子的回归计数

6 个答案: