如何使用 Linq 对象图导航创建逗号分隔的字符串

public class PatientViewModel
{
    public int PID { get; set; } 
    public string patientname { get; set; } 
    public virtual ICollection<Patient_VisitHistoryViewModel> Patient_VisitHistoryViewModelList { get; set; }
    public virtual ICollection<Patient_insurancecompaniesViewModel> Patient_insurancecompaniesViewModelList { get; set; }
}
public class Patient_VisitHistoryViewModel
{
    public int VID { get; set; } 
    public string visitstudylist { get; set; }
    public string visttype { get; set; } 
}
public class Patient_insurancecompaniesViewModel
{
    public int PINSID { get; set; } 
    public int PID { get; set; } 
    public int INSID { get; set; } 
    public string insurancecompanyname { get; set; }
}
public class Patient
{
    public int PID { get; set; } // PID (Primary key)
    public string patientname { get; set; } // patientname (length: 100)
        
    // Reverse navigation
    public virtual ICollection<Patient_insurancecompanies> Patient_insurancecompanies { get; set; } // Patient_insurancecompanies.FK_Patient_insurancecompanies_Patient
    public virtual ICollection<Visit> Visit { get; set; } // Visit.FK_Visit_Patient
}

public class Visit
{
    public int VID { get; set; } // VID (Primary key)
    public int PID { get; set; } // PID
    // Reverse navigation
    public virtual ICollection<Visit_studiesperformed> Visit_studiesperformed { get; set; } // Visit_studiesperformed.FK_visits_studiesperformed_visits
    // Foreign keys
    public virtual Branch Branch { get; set; } // FK_visits_branches
    public virtual Patient Patient { get; set; } // FK_Visit_Patient
    public virtual Visittype Visittype { get; set; } // FK_Visit_Visittype
}
public class Visit_studiesperformed
{
    public int VSPID { get; set; } // VSPID (Primary key)
    public int VID { get; set; } // VID
    public int STID { get; set; } // STID
    // Reverse navigation
    public virtual ICollection<Visit_studiesperformed_medicalreport> Visit_studiesperformed_medicalreport { get; set; } // Visit_studiesperformed_medicalreport.FK_visits_medicalreport_visits_studiesperformed
    // Foreign keys
    public virtual Studies Studies { get; set; } // FK_Visit_studiesperformed_studies
    public virtual Visit Visit { get; set; } // FK_visits_studiesperformed_visits
}
public class Studies
{
    public int STID { get; set; } // STID (Primary key)
    public string studydescription { get; set; } // studydescription (length: 100)
    // Reverse navigation
    public virtual ICollection<Visit_studiesperformed> Visit_studiesperformed { get; set; } // Visit_studiesperformed.FK_Visit_studiesperformed_studies
}
public class Insurancecompany
{
    public int INSID { get; set; } // INSID (Primary key)
    public string insurancecompanyname { get; set; } // insurancecompanyname (length: 100)
    // Reverse navigation
    public virtual System.Collections.Generic.ICollection<Patient_insurancecompanies> Patient_insurancecompanies { get; set; } // Patient_insurancecompanies.FK_Patient_insurancecompanies_Insurancecompany
}
public ActionResult Edit(int PID)
{
    Patient patient = bLLPatient.GetPatientByPID(PID);
  
    List<Insurancecompany> ListOfInsuranceCompany = bLLControltables.GetList_Insurancecompany();
    List<Studies> ListofStudies = bLLControltables.GetList_Studies();
    PatientViewModel patientViewModel = mapper.Map<PatientViewModel>(patient);
    patientViewModel.Patient_insurancecompaniesViewModelList.ToList().ForEach(x => x.insurancecompanyname = ListOfInsuranceCompany.Where(b => x.INSID == b.INSID).SingleOrDefault().insurancecompanyname);
   
    return View(patientViewModel);
}

看看我public ActionResult Edit(int PID)的底部. 我正在尝试制作一个逗号分隔的Studies.studydescription列表，并存储在 int 列表中 patientViewModel.Patient_VisitHistoryViewModelList.visitstudylist ...

我已经设法用这个代码完成了类似的事情patientViewModel.Patient_insurancecompaniesViewModelList

patientViewModel.Patient_insurancecompaniesViewModelList.ToList().ForEach(x => x.insurancecompanyname = ListOfInsuranceCompany.Where(b => x.INSID == b.INSID).SingleOrDefault().insurancecompanyname);

所以我要做的是：枚举Patient_VisitHistoryViewModelList，获取每次访问，每次访问获取每个Visit_studiesperformed，每次访问Vist_studyperformed获取每个studies.studydescription....

然后以某种方式制作一个逗号分隔的字符串并将其存储在每个patientViewModel.Patient_insurancecompaniesViewModelList.visitstudylist

我确实设法找到了一种方法来在此处制作逗号分隔的列表 自动映射器：收集到单字符串属性，但我在将其放在一起时遇到了问题。