.NET EF Core 按子集合属性排序

Question

我有一个具有导航属性 PatientGroupMemberships 的患者类，PatientGroupMembership 具有 PatientGroup 属性，PatientGroup 具有属性 Name。 我想按患者的第一个 PatientGroupMembership -> PatientGroup -> Name 属性排序（按名称排序）

public class Patient
{
  public List<PatientGroupMembership>? PatientGroupMemberships { get; set; }
}

public class PatientGroupMembership
{
  public PatientGroup? PatientGroup { get; set; }
}

public class PatientGroup
{
  public string? Name { get; set; }
}

问题的第一部分已解决，我按 PatientGroup Name 属性加载并排序 PatientGroupMemberships

var query = patients
                    .Include(x => x.PatientGroupMemberships!.OrderBy(pgm => pgm.PatientGroup!.Name))
                    .ThenInclude(p => p.PatientGroup)
                    .AsNoTracking();

当我尝试按第一个名称值排序时，由于某种原因，它无法正确排序结果

 private static IQueryable<Patient> SortByPatientGroups(IQueryable<Patient> query, bool isDescendingOrder)
    {
        var orderedQuery = isDescendingOrder
            ? query.OrderByDescending(x => x.PatientGroupMemberships
                .Select(pgm => pgm.PatientGroup.Name)
                .FirstOrDefault())
            : query.OrderBy(x => x.PatientGroupMemberships
                .Select(pgm => pgm.PatientGroup.Name)
                .FirstOrDefault());

        return orderedQuery;
    }

任何帮助将不胜感激！

Answer 1

你已经很接近了，但我认为你需要将

Select

移到

OrderBy

内。这尚未经过测试，但我认为如果您将（在本例中为第二子条款）更改为...

query.OrderBy(x => x.PatientGroupMemberships
                .OrderBy(pgm => pgm.PatientGroup.Name)
                .FirstOrDefault().Name);

...应该可以。