c# - 复杂对象的自动映射器映射

Question

我正在使用 Automapper 将我的模型对象映射到 DTO。在 DTO 中，主键应替换为相应的对象。为此，我使用了以下代码:

// Model class
public class SubDepartment
{
    public long Id { get; set; }
    public string Name { get; set; }
    public long? DepartmentId { get; set; }
    public DateTime LastUpdated { get; set; }
}

// DTO class
public class SubDepartmentDTO
{
    public long Id { get; set; }
    public string Name { get; set; }
    public Department Department { get; set; }
    public long EventCount { get; set; }
}

// Mapping code

 Mapper.CreateMap<Models.Event.SubDepartment, DTO.SubDepartment>().ForMember(dto => dto.Department,
                map => map.MapFrom(sd => Mapper.Map<Department, DTO.Department>(_departmentRepository.GetById(sd.DepartmentId.Value))));

但是当我在 Controller 中从 SubDepartment 映射到 SubDepartmentDTO 时，“部门”对象始终为空。我尝试用硬编码的 Department 对象替换 _departmentRepository.GetById(sd.DepartmentId.Value) 代码，它运行良好。我还验证了主键在数据库中是否存在相应的部门。谁能指出我做错了什么？

Answer 1

用这段代码试试

Mapper.CreateMap<Models.Event.SubDepartment, DTO.SubDepartment>().ForMember(dto => dto.Department,map => map.MapFrom(sd => _departmentRepository.GetById(sd.DepartmentId.Value)));

如果它不起作用你可以尝试自定义值解析器

Models.Event.SubDepartment, DTO.SubDepartment>().ForMember(dto => dto.Department, map => map.ResolveUsing<DepartmentResolver>());

public class DepartmentResolver: ValueResolver<Models.Event.SubDepartment,DTO.SubDepartment>
{
    Reporsitory _departmentRepository;
    protected override DTO.SubDepartment ResolveCore(Models.Event.SubDepartment source)
    {
        return _departmentRepository.GetById(source.DepartmentId.Value);
    }
}