我有一個Plan與多個子計劃（子計劃）相同的實體，每個子計劃都可以是null。對于PlanDto，我嘗試加載所有子代的列表，而不是像實體一樣為每個子代擁有一個單獨的屬性。我已經通過foreach循環手動實現了它，但是現在我試圖通過AutoMapper來實現它，由于某種原因而失敗了。實體：public class Plan{    public virtual int Id { get; set; }    public DateTime Date { get; set; }    public virtual PlanDetail PlanChild1 { get; set; }    public virtual ObservationCare PlanChild2 { get; set; }}public class PlanDetail{    public virtual int Id { get; set; }    public virtual Plan Plan { get; set; }    public virtual string Description { get; set; }}public class ObservationCare{    public virtual int Id { get; set; }    public virtual Plan Plan { get; set; }    public virtual string Description { get; set; }}DTO：public class PlanDto: EntityDto{    public DateTime Date { get; set; }    public IEnumerable<ChildPlan> ChildPlan { get; set; }}public class ChildPlan : EntityDto{    public ChildPlanType Type { get; set; }}public enum ChildPlanType{    PlanDetail,    ObservationCare}AutoMapper配置：configuration.CreateMap<Plan, PlanDto>();configuration.CreateMap<PlanDetail, ChildPlan>()    .ForMember(dto => dto.Type, options => options.MapFrom(p => ChildPlanType.PlanDetail));configuration.CreateMap<ObservationCare, ChildPlan>()    .ForMember(dto => dto.Type, options => options.MapFrom(p => ChildPlanType.ObservationCare));映射嘗試：var output = new List<PlanDto>();var plans = await _planRepository.GetAll().ToList();foreach (var plan in plans){    output.Add(ObjectMapper.Map<PlanDto>(plan));}我不知道為什么列表中的ChildPlanDTOoutput總是如此null！