我正在用LINQ写一个问题加入李。如何获得包含3个表组合的结果表?我必须将表格合并在一行中。 有什么想法吗?
Peole
---------------
Id | 1 Id |2
Name | David Name |Ameyy
Surname| David1 Surname |Ameyy2
Appointment
---------------
Id |19
PeopleId |1
Subject |description
Participant
---------------
Id |1 Id |2
AppointmentId |19 AppointmentId |19
PeopleId |1 PeopleId |2
Result
----------------------------------
Id | 1
Subject | Subject
Participant| David David1, Ameyy Ameyy2
Linq查询;
IQueryable<AppointmentPoolModel> query = db.Randevu.Join(db.Kisi,
appointment => appointment .TALEPEDENKISI,
people=> people.ID,
(appointment , people)
=> new AppointmentPoolModel
{
Id = appointment.ID,
Subject = appointment.Subject,
Note = appointment .NOTLAR,
NameSurname = people.Name+ " " + people.Surname,
RequestedId = people.ID,
//Participan = string.Join(",", )
});
var result = query.OrderBy(appointment => randevu.AppointmentStartDate).ToList();
答案 0 :(得分:0)
您应该逐步进行调查。
这里有一个带有两个专用连接和一个groupBy的示例(在您的情况下缺少):
public class People
{
public int Id { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
}
public class Appointment
{
public int Id { get; set; }
public string Subject { get; set; }
}
public class Participation
{
public int Id { get; set; }
public int PeopleId { get; set; }
public int AppointmentId { get; set; }
}
static void Main(string[] args)
{
// Example-Data (Would have helped in this format ;))
List<People> people = new List<People>()
{
new People() { Id = 1, Surname = "David1", Name = "David"},
new People() { Id = 2, Surname = "Ameyy2", Name = "Ameyy"}
};
List<Appointment> appointments = new List<Appointment>()
{
new Appointment() { Id = 1, Subject = "description" }
};
List<Participation> participations = new List<Participation>()
{
new Participation() { Id = 1, PeopleId = 1, AppointmentId = 1 },
new Participation() { Id = 1, PeopleId = 2, AppointmentId = 1 }
};
Console.WriteLine("***** JOIN appointment to participation *****");
// At the beginning we want to join the table 'Appointment' with the n-to-n-Table "Participation".
var AppointmentsAndParticipations = appointments.Join
(
participations, // Other table to connect
a => a.Id, // Key in 1st table
p => p.AppointmentId, // Key in 2nd table
(a, p) => new { Appointment = a, PeopleId = p.PeopleId } // build new row
);
foreach (var item in AppointmentsAndParticipations)
{
// The result should be out appointment and the peopleId. We got "Appointment.Count*Participations.Count" rows
Console.WriteLine(item.Appointment.Id.ToString().PadLeft(5) + ", " + item.Appointment.Subject.PadLeft(15) + ", " + item.PeopleId);
}
Console.WriteLine("***** JOIN people *****");
// We need to join the people which belong to the Ids in participation
var AppointmentsAndPeople = AppointmentsAndParticipations.Join
(
people, a => a.PeopleId, // Similar to 1st join...
p => p.Id,
(a, p) => new { Appointment = a.Appointment, People = p }
);
foreach (var item in AppointmentsAndPeople)
{
Console.WriteLine(item.Appointment.Id.ToString().PadLeft(5) + ", " + item.Appointment.Subject.PadLeft(15) + ", " + item.People.Name + " " + item.People.Surname);
}
Console.WriteLine("***** Group the rows *****");
// Now we want to group the rows back to Appointment-Level. We group by Appointment and People will be out elements to be sum-up
var AppointmentPools = AppointmentsAndPeople.GroupBy
(
key => key.Appointment, // Select the 'column' which shall be the keys
group => group.People, // Select the 'column' which will be converted to a single value (like count, sum, max ..or in your case string.join())
(key, group) => new // Build the output object..
{
Id = key.Id,
Subject = key.Subject,
Participants = string.Join(", ", group.Select(s => s.Name + " " + s.Surname))
}
);
foreach (var item in AppointmentPools)
{
Console.WriteLine("Id: " + item.Id + ", Subject: " + item.Subject + ", Participants: " + item.Participants);
}
}
答案 1 :(得分:0)
你可以试试这个。
var qPeoples = Participants.Join(Peoples,
pr => pr.PeopleId,
pe => pe.Id,
(pr, pe) => new { Part = pr, People = pe });
var result = Appointments.Select(app => new
{
app.Id,
app.Subject,
Participant = String.Join(",", qPeoples.Where(q => q.Part.AppointmentId == app.Id)
.Select(s => new
{ FullName = String.Format( "{0} {1}"
, s.People.Name, s.People.Surname ) } ) )
}).ToList();