通過ThenInclude與EF相關的數據

Question

在EF Core中返回相關數據的正確，最高效的方法是什么？

我正在使用聯接表UserProjects來表示用戶和項目之間的多對多關系。

（用戶）1 --- M（UserProject）M --- 1（項目）1 --- M（文件）

如何為當前用戶返回特定項目上的所有文件？

我目前正在這樣做：

var userId = new Guid(_userManager.GetUserId(User));

var files = _dbContext.Users
                    .Include(up => up.UserProjects)
                    .ThenInclude(p => p.Project)
                    .ThenInclude(f => f.Files)
                    .Where(u => u.Id == userId)
                    .Single()
                    .UserProjects.Select(up => up.Project)
                    .Where(p => p.Id == projectId)
                    .Single().Files.ToList();

楷模：

public class ApplicationUser : IdentityUser<Guid>
{
    public virtual ICollection<UserProject> UserProjects { get; set; }
}

public class UserProject
{
    public Guid ApplicationUserId { get; set; }
    public ApplicationUser User { get; set; }

    public Guid ProjectId { get; set; }
    public Project Project { get; set; }
}

public class Project
{
    public Guid Id { get; set; }
    public string Name { get; set; }

    public virtual ICollection<UserProject> UserProjects { get; set; }
    public virtual ICollection<File> Files { get; set; }

}

public class File
{
    public Guid Id { get; set; }
    public string Name { get; set; }

    [Required]
    public Project Project { get; set; }

}

Answer 1

試試這個。

var userId = new Guid(_userManager.GetUserId(User));

var files = _dbContext.Files
               .Include(p => p.Project)
               .ThenInclude(up => up.UserProjects)
               .ThenInclude(u => u.User)
               .Where(x => x.Project.UserProjects.User.Id == userId)
               .ToList();