C# 如何在C.NET内核中自动映射特定条件？

我想在我的特定DTO中自动映射fill Worker类别键，但我不知道如何做。我在构建解决方案时没有遇到任何错误，但是当我进行API调用时，它会触发一个错误

你能帮我吗

public class WorkerRD
    {
        public int Id { get; set; }
        public string Login { get; set; }
        public string Role { get; set; }
        public string Firstname { get; set; }
        public string Lastname { get; set; }
        public string AvatarUrl { get; set; }
        public string Iso { get; set; }
        public string Sexe { get; set; }
        public string Email { get; set; }
        public string Phone { get; set; }
        public int WorkerCategoryKey { get; set; }
        public string Address { get; set; }
        public string Postcode { get; set; }
        public string Locality { get; set; }

        public IEnumerable<TrWorkerToWorkerCategory> trWorkerToWorkerCategory { get; set; }
    }

CreateMap<TUser, WorkerRD>()
                .ForMember(
                    dest => dest.Firstname,
                    opt => opt.MapFrom(src => src.TWorker.Firstname)
                ).ForMember(
                    dest => dest.Lastname,
                    opt => opt.MapFrom(src => src.TWorker.Lastname)
                ).ForMember(
                    dest => dest.Email,
                    opt => opt.MapFrom(src => src.TWorker.Email)
                ).ForMember(
                    dest => dest.Phone,
                    opt => opt.MapFrom(src => src.TWorker.Phone)
                ).ForMember(
                    dest => dest.Sexe,
                    opt => opt.MapFrom(src => src.TWorker.Sexe)
                ).ForMember(
                    dest => dest.Address,
                    opt => opt.MapFrom(src => src.TWorker.Address)
                ).ForMember(
                    dest => dest.Postcode,
                    opt => opt.MapFrom(src => src.TWorker.Postcode)
                ).ForMember(
                    dest => dest.Locality,
                    opt => opt.MapFrom(src => src.TWorker.Locality)
                ).ForMember(
                    dest => dest.WorkerCategoryKey,
                    opt => opt.MapFrom(src => src.TWorker.TrWorkerToWorkerCategory.Where(tr => tr.IsDefault == true).Select(cat => cat.WorkerCategoryKey))
                ).ForMember(
                    dest => dest.trWorkerToWorkerCategory,
                    opt => opt.MapFrom(src => src.TWorker.TrWorkerToWorkerCategory.Where(tr => tr.IsDefault == true))
                );

---

您的映射不起作用，因为无法简单地将集合映射。请选择cat=>cat.WorkerCategoryKey，将其映射到单个值dest.trworkerTowWorkerCategory。理解这一点的简单方法是手动执行类似的映射：

列表源=新列表{1,2,3}； int destination=源； 这没有任何意义，但本质上这就是您告诉AutoMapper如何处理WorkerCategoryKey的当前映射

话虽如此，说清楚你需要做什么并不容易，因为这取决于数据。但不管是什么，您都需要源为单个int。例如，如果源始终是同一WorkerCategoryKey的集合，则您可以从中获取第一项。选择cat=>cat.WorkerCategoryKey:

福门博先生 dest=>dest.WorkerCategoryKey， opt=>opt.MapFromsrc=>src.TWorker.trworkerTowWorkerCategory.Wheretr=>tr.IsDefault==true.Selectcat=>cat.WorkerCategoryKey.First

---

嗨@devNull我试过你的解决方案，但没用。无法将bool转换为int。@Mathlan89刚刚更新，应该是。Selectcat=>cat.WorkerCategoryKey.Firstfantastic，它可以工作，这正是我需要的：-非常感谢您的帮助！我已经接近解决方案，但我没有设定第一个：

.ForMember(
                    dest => dest.WorkerCategoryKey,
                    opt => opt.MapFrom(src => src.TWorker.TrWorkerToWorkerCategory.Where(tr => tr.IsDefault == true).Select(cat => cat.WorkerCategoryKey))