[英]Automapper - Multi object source and one destination
我正在使用自动映射器来映射多个对象(db 类到 ui 对象)。
地图1:
Mapper.CreateMap<sourceone, destination>().ForMember(sss => sss.one, m => m.MapFrom(source => source.abc));
地图2:
Mapper.CreateMap<sourcetwo, destination>().ForMember(sss => sss.two, m => m.MapFrom(source => source.xyz));
destination d = new destination();
//地图1
d = AutoMapper.Mapper.Map<sourceone, destination>(sourceone);
//地图2
d = AutoMapper.Mapper.Map<sourcetwo, destination>(sourcetwo);
一旦我调用“地图 2”,使用地图 1 填充的值就会丢失..(即destination.one 变为空)。 我该如何解决?
Map
有一个带有源和目标对象的重载:
d = AutoMapper.Mapper.Map<sourceone, destination>(sourceone);
/* Pass the created destination to the second map call: */
AutoMapper.Mapper.Map<sourcetwo, destination>(sourcetwo, d);
mapper.MergeInto<PersonCar>(person, car)
将接受的答案作为扩展方法,简单和通用版本:
public static TResult MergeInto<TResult>(this IMapper mapper, object item1, object item2)
{
return mapper.Map(item2, mapper.Map<TResult>(item1));
}
public static TResult MergeInto<TResult>(this IMapper mapper, params object[] objects)
{
var res = mapper.Map<TResult>(objects.First());
return objects.Skip(1).Aggregate(res, (r, obj) => mapper.Map(obj, r));
}
为每个输入类型配置映射后:
IMapper mapper = new MapperConfiguration(cfg =>
{
cfg.CreateMap<Person, PersonCar>();
cfg.CreateMap<Car, PersonCar>();
}).CreateMapper();
public class Person
{
public string Name { get; set; }
public string PhNo { get; set; }
}
public class Company
{
public int EmpNo { get; set; }
public string Title { get; set; }
}
public class PersonCompany
{
public string Name { get; set; }
public string PhNo { get; set; }
public int EmpNo { get; set; }
public string Title { get; set; }
}
//you can test as below
var pMap = Mapper.CreateMap<Person,PersonCompany>();
pMap.ForAllMembers(d => d.Ignore());
pMap.ForMember(d => d.Name, opt => opt.MapFrom(s => s.Name))
.ForMember(d => d.PhNo, opt => opt.MapFrom(s => s.PhNo));
var cMap = Mapper.CreateMap<Company, PersonCompany>();
cMap.ForAllMembers(d => d.Ignore());
cMap.ForMember(d => d.EmpNo, opt => opt.MapFrom(s => s.EmpNo))
.ForMember(d => d.Title, opt => opt.MapFrom(s => s.Title));
var person = new Person { Name = "PersonName", PhNo = "212-000-0000" };
var personCompany = Mapper.Map<Person,PersonCompany>(person);
var company = new Company { Title = "Associate Director", EmpNo = 10001 };
personCompany = Mapper.Map(company, personCompany);
Console.WriteLine("personCompany.Name={0}", personCompany.Name);
Console.WriteLine("personCompany.PhNo={0}", personCompany.PhNo);
Console.WriteLine("personCompany.EmpNo={0}", personCompany.EmpNo);
Console.WriteLine("personCompany.Title={0}", personCompany.Title);
根据我的说法,您应该避免调用重载的 Map 方法来获取目标对象的实例,如已接受的答案中所述。 这不会让您测试/验证您的映射配置( Mapper.Configuration.AssertConfigurationIsValid()
),否则您将在映射中添加很多“忽略”。
一个非常简单的解决方案是创建一个包含源引用的复合类型,并根据该复合类型定义到目标的映射。
就像是:
public class SourceOneTwo
{
public SourceOne SourceOne { get; set; }
public SourceTwo SourceTwo { get; set; }
}
static void Main(string[] args)
{
var config = new MapperConfiguration(cfg =>
cfg.CreateMap<SourceOneTwo, Destination>()
.ForMember(dest => dest.one, m => m.MapFrom(source => source.SourceOne.abc))
.ForMember(dest => dest.two, m => m.MapFrom(source => source.SourceTwo.xyz)));
config.AssertConfigurationIsValid();
}
现在看起来是这样的:
DestinationDto = _mapper.Map(source2, _mapper.Map<source1type, destinationType>(source1));
只是想补充一点,现在您可以使用元组语法来定义多种类型的映射。
// configuring
Mapper
.CreateMap<(SourceType1 Source1, SourceType2 Source2), DestinationType>()
.ForMember(sss => sss.one, m => m.MapFrom(source => source.Source1.abc))
.ForMember(sss => sss.two, m => m.MapFrom(source => source.Source2.xyz));
// using
var result = Mapper.Map<DestinationType>((source1, source2));
优点:
缺点:
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