Select()在ThenInclude()中不起作用

我正在嘗試檢索movie具有screenings串列的物件。中的每個物件screenings都有一個theater物件，而該物件又具有一個screenings串列。我試圖擺脫那個screenings串列，theater所以我創建了一個theaterDTO模型。

我正在努力實作的目標

    var x = _context.Movies
                .Where(m => movieId == m.Id)
                .Include(m => m.Screenings)

這導致screening串列被多次檢索：在movie物件中和在每個theater物件中movie.theaters

這是Screening課程：

public class Screening : BaseEntity
    {
        public Theater Theater { get; set; }
        public Movie Movie { get; set; }
        public DateTime Time { get; set; }

        public ICollection<Booking> Bookings { get; set; }    
        public Screening()
        {
            Bookings = new List<Booking>();
        }
    }

Movie：

public class Movie : BaseEntity
    {
        public string Name { get; set; }
        public string Body { get; set; }
        public string Dir { get; set; }
        public string Pic { get; set; }

        public ICollection<Screening> Screenings { get; set; }
        public Movie()
        {
            Screenings = new List<Screening>();
        }
    }

Theater：

public class Theater : BaseEntity
    {
        public string Address { get; set; }
        public string Name { get; set; }

        public ICollection<Screening> Screenings { get; set; }
        public Theater()
        {
            Screenings = new List<Screening>();
        }
    }

TheaterDTO：

public class TheaterDTO 
    {
        public string Address { get; set; }
        public string Name { get; set; }
    }

功能：

[HttpGet]
    [Route("{movieId}")]
    public Movie GetMovieById(Guid movieId)
    {
        return _context.Screenings
            .Where(m => movieId == m.Id)
            .Select(x => new TheaterDTO
            {
                Name = x.Theater.Name,
                Address = x.Theater.Address
            }).FirstOrDefault();
    }

uj5u.com熱心網友回復：

首先定義一個 MovieDTO：

public class MovieDTO
{
    public string Name { get; set; }
    public string Body { get; set; }
    public string Dir { get; set; }
    public string Pic { get; set; }
    public List<ScreeningDTO> Screenings { get; set; }
}

public class ScreeningDTO
{
    public TheaterDTO Theater { get; set; } 
}

public class TheaterDTO
{
    public string Address { get; set; }
    public string Name { get; set; }
}

采取這樣的資料：

var x = _context.Movies
            .Where(m => movieId == m.Id)
            .Include(m => m.Screenings)
               .ThenInclude(s => s.Theater)
            .Where(p => p.Id == movieId)
            .Select(p => new MovieDTO {
                      Name = p.Name,
                      Body = p.Body,
                      Dir = p.Dir,
                      Pic = p.Pic,
                      Screening = p.Screenings.Select(x => new ScreeningDTO {
                                     Theater = new TheaterDTO {
                                        Name = x.Theater.Name,
                                        Address = x.Theater.Address
                                    }
                       }).ToList()
                    }).FirstOrDefault();
               

標籤：C＃ asp.net 实体框架 asp.net核心

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