使用OData和AutoMapper展开子导航属性时“序列不包含匹配元素”

尝试使用以下查询展开导航属性时出现异常“Sequence contains no matching element”: http://localhost:5000/odata/users ?$expand=角色。没有$expand关键字的请求有效。从接收DTO对象 AutoMapper

实体框架实体:

public class User {
  public string Id { get; set; }
  public string Username { get; set; }
  public string Email { get; set; }
  public virtual ICollection<UserRole> UserRoles { get; set; }
}

public class Role {
  public string Id { get; set; }
  public string Name { get; set; }
}

public class UserRole {
  public string UserId { get; set; }
  public string RoleId { get; set; }
}

DTO型号:

public class UserModel {
  public string Id { get; set; }
  public string Username { get; set; }
  public string Email { get; set; }
  public IEnumerable<RoleModel> Roles { get; set; }
}

public class RoleModel
{
    public string Id { get; set; }
    public string Name { get; set; }
}

配置:

CreateMap<UserRole, RoleModel>()
     .ForMember(x => x.Id, x => x.MapFrom(m => m.UserId))
     .ForMember(x => x.Name, x => x.MapFrom(m => m.Role.Name));

CreateMap<User, UserModel>()
     .ForMember(dest => dest.Roles, opts => opts.MapFrom(src => src.UserRoles))
     .ReverseMap()
     .ForMember(dest => dest.UserRoles, o => o.Ignore());

控制器动作方法:

[HttpGet]
[EnableQuery]
public IQueryable<UserModel> Get() =>
    _userManager.Users.ProjectTo<UserModel>(_mapper.ConfigurationProvider);

Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.Internal.CorrelatedCollectionOptimizingVisitor 当它试图在由生成的表达式中查找where子句时

var originalCorrelationPredicate = collectionQueryModel.BodyClauses
    .OfType<WhereClause>()
    .Single(c => c.Predicate is NullSafeEqualExpression);

如果我更改 汽车制造商 对于以下情况,不会引发异常,但会对每个用户记录分别执行角色子查询:

CreateMap<User, UserModel>()
    .ForMember(dest => dest.Roles, opts => 
          opts.MapFrom(src => 
              src.UserRoles.Select(ur => new RoleModel {
                    Id = ur.UserId,
                    Name = ur.Role.Name
                })))
    .ReverseMap()
    .ForMember(dest => dest.UserRoles, o => o.Ignore());

我做错了什么?

补充:

手写变体(按其应有的方式工作):

.......
Roles = .Call System.Linq.Enumerable.Select(
     $x.UserRoles,
     .Lambda 
#Lambda2<System.Func`2[Test.Data.UserRole,Test.Models.RoleModel]>),
.......

由AutoMapper生成:

.......
Roles = .Call System.Linq.Enumerable.ToList(.Call 
     System.Linq.Enumerable.Select(
           $x.UserRoles,
           .Lambda 
#Lambda2<System.Func`2[Test.Data.UserRole,Test.Models.RoleModel]>)),
.......

汽车制造商 ToList() ?