列出IQueryable对象内部

本文关键字：内部 对象 IQueryable 列出 | 更新日期: 2023-09-27 18:29:54

给定以下条件：

public class Person
{
  public int ID { get; set;}
  public string Name { get; set;}
  public IQueryable<Pet> Pets { get;set; }
}
public class Pet
{
  public int id { get; set; }
  public int OwnerId { get; set; }
  public string Name { get; set; }
}
public class SearchCriteria
{
  public string PersonName {get; set; }
  public List<string> PetNames {get; set;}
}

使用IQueryable 进行搜索时，选择所有带宠物的人

public List<Person> GetWithPets(SearchCriteria search)
{
     var people = (from p in context.People
                   where p.Name == search.PersonName
                   select new Person{
                          ID = p.ID,
                        Name = p.Name,
                        Pets = (from pt in context.Pets
                                where pt.OwnerId == p.ID
                                select new Pet {
                                   id = pt.ID,
                                 OwnerId = pt.OwnerId,
                                 Name = pt.Name
                                }).AsQueryable
                   }).AsQueryable();
       foreach(var str in search.PetNames)
       {
            people = people.Where(o=>o.Pets.Any(p=>p.Name == str));
       }
  return people.ToList();
}

我的问题是，无论搜索名称的foreach是什么，在返回的人员列表中，pets都是null，即使有和那个人有关联的宠物，我哪里错了？

编辑：

public class Person
{
    public int ID { get; set; }
    public string Name { get; set; }
    public IQueryable<Animal> Pets { get; set; }
}
public class Animal
{
    public int id { get; set; }
    public int? OwnerId { get; set; }
    public string Name { get; set; }
}
public class SearchCriteria
{
    public string PersonName { get; set; }
    public List<string> PetNames { get; set; }
}

class Program
{
    public static List<Person> GetWithPets(SearchCriteria search)
    {
        using (DatabaseEntities context = new DatabaseEntities())
        {
            var people = (from p in context.Peoples
                          where p.Name == search.PersonName
                          select new Person
                          {
                              ID = p.ID,
                              Name = p.Name,
                              Pets = (from pt in context.Pets
                                      where pt.OwnerID == p.ID
                                      select new Animal
                                      {
                                          id = pt.ID,
                                          OwnerId = pt.OwnerID,
                                          Name = pt.Name
                                      }).AsQueryable()
                          }).AsQueryable();
            foreach (var str in search.PetNames)
            {
                people = people.Where(o => o.Pets.Any(p => p.Name == str));
            }
            return people.ToList();
        }
    }

列出IQueryable对象内部

如果Person和Pet是模型的实体，则Person.Pets是Pet实体的导航属性，则您希望拥有完整的Person实体和所有完整的Pet实体，并参考您的评论。。。

我的方法应该返回name等于的人的列表搜索人名&他们所有的宠物，但只有那些拥有搜索中有这些名字的宠物。宠物名称

你可以使用这个：

public List<Person> GetWithPets(SearchCriteria search)
{
    var people = from p in context.People.Include("Pets")
                 where p.Name == search.PersonName
                    && p.Pets.Any(pt => search.PetNames.Contains(pt.Name))
                 select p;
    return people.ToList();
}

或者您可以尝试类似的东西

foreach(var str in search.PetNames)
       {
            people.Concat(people.Where(o=>o.Pets.Any(p=>p == str)).Include('Pet'));
       }

你可以试试这个吗

var people = (from p in context.People
                   where p.Name == search.PersonName
                   select new Person{
                          ID = p.ID,
                        Name = p.Name,
                        Pets = (from pt in context.Pets
                                where pt.OwnerId == p.ID
                                select new Pet {
                                   id = pt.ID,
                                 OwnerId = pt.OwnerId,
                                 Name = pt.Name
                                })
                   }).Include("Pets").AsQueryable();

将AsQueryable()添加到Pets集合：

Pets = (from pt in context.Pets  
        where pt.OwnerId == p.ID  
        select new Pet {  
            id = pt.ID,  
            OwnerId = pt.OwnerId,  
            Name = pt.Name  
        }).AsQuerable()
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