c# - 有条件地将一种源类型映射到两种目标类型

Question

我有一个像这样的源DTO

public class Member 
{
    public string MemberId {get;set;}
    public string MemberType {get;set;}
    public string Name {get;set;}
}

成员类型可以是“个人”或“公司”。

还有两个像这样的目标类

public class PersonMember 
{
    public int PersonMemberId {get;set;}
    public string Name {get;set;}
}

public class CompanyMember 
{
    public int CompanyMemberId {get;set;}
    public string Name {get;set;}
}

我想使用 Automapper 检查源类中 MemberType 的值是什么，并根据该类型映射到两个目标类型之一。

我看到了 conditionally mapping 的例子，但它会映射执行条件检查的字段。我想检查条件并映射不同的字段。

var config = new MapperConfiguration(cfg => {
  cfg.CreateMap<Foo,Bar>()
    .ForMember(dest => dest.baz, opt => opt.Condition(src => (src.baz >= 0))); 
});

我的目标是这样的——

cfg.CreateMap<Member, PersonMember>()
.ForMember(dest => PersonMember.PersonMemberId, opt => if the source.MemberType == "Person" perform mapping from MemberId, otherwise do nothing);

cfg.CreateMap<Member, CompanyMember>()
.ForMember(dest => CompanyMember.CompanyMemberId, opt => if the source.MemberType == "Company" perform mapping from MemberId, otherwise do nothing);

Answer 1

引入一些基类Member .继承PersonMember , CompanyMember来自新的基类。

然后定义这些映射:

cfg.CreateMap<Dto.Member, Member>()
    .ConstructUsing((memberDto, context) => {
    switch (memberDto.MemberType)
    {
        case "PersonMember":
            return context.Mapper.Map<PersonMember>(memberDto);
        case "CompanyMember":
            return context.Mapper.Map<CompanyMember>(memberDto);
        default:
            throw new ArgumentOutOfRangeException($"Unknown MemberType {memberDto.MemberType}");
    }
});

cfg.CreateMap<Dto.Member, PersonMember>()
    .ForMember(dest => PersonMember.PersonMemberId,
               opt => opt.MapFrom(src => src.MemberId));

cfg.CreateMap<Dto.Member, CompanyMember>()
    .ForMember(dest => CompanyMember.CompanyMemberId,
               opt => opt.MapFrom(src => src.MemberId));

现在您可以使用 _mapperInstance.Map<Member>(memberDto); 进行映射