有条件地将一种源类型映射到两种目标类型

问题描述

我有这样的源DTO

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

成员类型可以是人"或公司".

The member type can be "Person" or "Company".

还有两个这样的目标类

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，并根据该类型将其映射到两种目标类型之一.

I want to use Automapper to check what the value of MemberType is in the source class and depending on that type, map to one of the two destination types.

我看到了有条件地映射的示例，但是它映射了它的字段执行条件检查.我想检查条件并映射其他字段.

I saw the example of conditionally mapping, but it maps the field it performs the conditional check on. I want to check the condition and map a different field.

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

我的目标就是这样-

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);

推荐答案

使用自动映射器，必须在调用映射器上指定返回类型，例如. mapper.Map<PersonMember>(member)，这表明返回类型为PersonMember，因此您无法返回CompanyMember.

With automapper you must specify return type on invocation mapper eg. mapper.Map<PersonMember>(member), this tells that return type is PersonMember so you can't return CompanyMember.

您可以执行以下操作:

var configPerson = new MapperConfiguration(cfg => cfg.CreateMap<Member, PersonMember>());
var configCompany = new MapperConfiguration(cfg => cfg.CreateMap<Member, CompanyMember>());

PersonMember personMember = null;
CompanyMember companyMember = null;

switch (member.MemberType )
{
    case "PersonMember":
        var mapper = configPerson.CreateMapper();
        personMember = mapper.Map<PersonMember>(member);
        break;
    case "CompanyMember":
        var mapper = configCompany.CreateMapper();
        companyMember = mapper.Map<CompanyMember>(member);
        break;
    default:
        throw new Exception("Unknown type");
        break;
}

或者您可以尝试将自定义类型转换器与object一起使用作为返回类型.

Or you can try Custom type converters with object as return type.

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