Linq EF Include() with Select() new type lost include

Question

context.Projects
.Include(x => x.Members) //List<Member> public class Member
.Include(x => x.Members.Select(z => z.City)) //public class City
.ToList(); 

从项目中选择

包括project.Members列表

包括每个project.Members.City

需要在结果中添加一些数据

context.Projects
.Include(x => x.Members) 
.Include(x => x.Members.Select(z => z.City)) 
.Select(x => new {
    Project = x,
    Amount = 22
})
.ToList(); 

Project 属性已填充，但 Members 为空

问题 1 - 如何在 new { Project = x }

中包含 Project.Members

下一个

context.Projects
.Include(x => x.Members) //List<Member>
.Include(x => x.Members.Select(z => z.City)) //City is navigation property
.Select(x => new {
    Project = x,
    Members = x.Members,
    Amount = 22
})
.ToList(); 

Project 属性已填充，Members 已填充，但 Members[0].City 为空

问题 2 - 如何填写 Members[0].City

附言

实体框架 6

public class Project
{
    public Guid Id { get; set; }
    public string Name { get; set; }
    public List<ProjectMember> Members { get; set; }
}

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

    public Guid CityId { get; set; }
    public City City { get; set; }
}

附言

这项工作 - 但代码开销

context.Projects
.Include(x => x.Members) //List<Member>
.Include(x => x.Members.Select(z => z.City)) //City is navigation property
.Select(x => new {
    Project = x,
    Members = x.Members.Select(z => new {
        Item = z,
        City= z.City
    }).ToList(),
    Amount = 22
})
.ToList(); 

Answer 1

您在包含后执行的任何操作（过滤除外）都会导致包含被丢弃。通过在包含后调用AsEnumerable，您将确保查询被执行，其余操作将在内存中完成：

context.Projects 
       .Include(x => x.Members) 
       .Include(x => x.Members.Select(z => z.City))
       .AsEnumerable() 
       .Select(x => new { Project = x, Amount = 22 }) 
       .ToList(); 

Answer 2

将您的导航属性声明为虚拟，列表为​​ ICollection，并让 EF 在水合您的实体时替换为它的具体实现：

public class Project
    {
        public Project { 
            Members = new HashSet<ProjectMember>(); 
        }
        public Guid Id { get; set; }
        public string Name { get; set; }
        public virtual ICollection<ProjectMember> Members { get; set; }
    }

    public class ProjectMember
    {
        public Guid ProjectId { get; set; }
        public virtual Project Project { get; set; }

        public Guid CityId { get; set; }
        public virtual City City { get; set; }
    }