C# 使用带连接的linq查询查询嵌套对象
我从api获得以下json结构:C# 使用带连接的linq查询查询嵌套对象,c#,json.net,linq-to-objects,C#,Json.net,Linq To Objects,我从api获得以下json结构: { "event_instance": [ { "id": 55551244, "event_id": 11112, "name": "Brown Belt Karate Class", "staff_members": [ { "id": 12345,
{
"event_instance": [
{
"id": 55551244,
"event_id": 11112,
"name": "Brown Belt Karate Class",
"staff_members": [
{
"id": 12345,
"name": "John Smith"
}
],
"people": [
{
"id": 111,
"name": "Jane Doe"
},
{
"id": 222,
"name": "Josh Smith"
},
{
"id": 333,
"name": "Ben Johnson"
}
],
"visits": [
{
"id": 1234578,
"person_id": 111,
"state": "completed",
"status": "complete"
},
{
"id": 1239865,
"person_id": 222,
"state": "completed",
"status": "complete"
},
{
"id": 1239865,
"person_id": 333,
"state": "canceled",
"status": "cancel"
}
]
}
]
}
我正在使用JSON.net将其反序列化为以下.net对象:
[JsonObjectAttribute("event_instance")]
public class EventInstance
{
[JsonPropertyAttribute("id")]
public int Id { get; set; }
[JsonPropertyAttribute("event_id")]
public int EventId { get; set; }
[JsonPropertyAttribute("name")]
public string Name { get; set; }
[JsonPropertyAttribute("staff_members")]
public List<StaffMember> StaffMembers { get; set; }
[JsonPropertyAttribute("visits")]
public List<Visit> Visits { get; set; }
[JsonPropertyAttribute("people")]
public List<Student> Students { get; set; }
}
[JsonObjectAttribute("staff_members")]
public class StaffMember
{
[JsonPropertyAttribute("id")]
public int Id { get; set; }
[JsonPropertyAttribute("name")]
public string Name { get; set; }
}
[JsonObjectAttribute("people")]
public class People
{
[JsonPropertyAttribute("id")]
public int Id { get; set; }
[JsonPropertyAttribute("name")]
public string Name { get; set; }
}
[JsonObjectAttribute("visits")]
public class Visits
{
[JsonPropertyAttribute("id")]
public int Id { get; set; }
[JsonPropertyAttribute("person_id")]
public int PersonId { get; set; }
[JsonPropertyAttribute("state")]
public string State { get; set; }
[JsonPropertyAttribute("status")]
public string Status { get; set; }
}
上面的工作很好,为我提供了上述json结构的精确对象表示。现在我尝试查询这个事件对象,以筛选/投影到一个新的结构,然后将其序列化回json并发送到浏览器。我需要返回事件中处于“已完成”状态和“已完成”状态的学生列表。如您所见,people数组与visits数组关联(带有id和person_id)。我希望生成以下简单输出:
var studentList = from theClass in event
from staff in theClass.StaffMembers
from student in theClass.People
from visits in theClass.Visits
where visits.Status == "complete"
&& visits.State == "completed"
select new
{
event_id = theClass.EventId
class_name = theClass.Name,
instructor_name = staff.Name,
student_id = student.Id,
student_name = student.Name
};
string _data = JsonConvert.SerializeObject(studentList);
这自然会产生重复的学生姓名。我是linq的新手。基本上,我需要加入/绑定人员和访问数组,因此我只需要为该id返回一个学生,以及此事件的根数据。任何关于更好的方法的建议都非常感谢 诀窍是将学生和访问加入一个包含以下两方面数据的集合:
from ei in eventInstances
from sm in ei.StaffMembers
from x in
(from vi in ei.Visits
join st in ei.Students on vi.PersonId equals st.Id
select new { vi, st }) // Here you get students and visits side-by-side
select new
{
ei.EventId,
Event = ei.Name,
StaffMemeber = sm.Name,
PersonId = x.st.Id,
Student = x.st.Name
}
啊,现在说得通了。林克需要一些时间来适应。谢谢
from ei in eventInstances
from sm in ei.StaffMembers
from x in
(from vi in ei.Visits
join st in ei.Students on vi.PersonId equals st.Id
select new { vi, st }) // Here you get students and visits side-by-side
select new
{
ei.EventId,
Event = ei.Name,
StaffMemeber = sm.Name,
PersonId = x.st.Id,
Student = x.st.Name
}