Description
Permet le mapping d'un objet de type A vers un objet de type B.
AutoMapper utilise des convention de mapping afin de réduire le paramétrage:
- Propriétés de même nom
- Flattening
- Ignore les références null
Liens
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var config = new MapperConfiguration(cfg => {
// configure mapping from Source to Dest
cfg.CreateMap<Source, Dest>();
// load the configuration from AppProfile
cfg.AddProfile<AppProfile>();
// load the configuration from all classes who inherits from Profile in the current assembly
cfg.AddProfiles(typeof(ContainerConfig).Assembly);
});
IMapper mapper = config.CreateMapper();
IMapper mapper = new Mapper(config);
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| AProfile.cs
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internal sealed class AProfile : Profile
{
public AProfile()
{
this.CreateAToBMapping();
this.CreateBToAMapping();
}
private void CreateAToBMapping()
{
this.CreateMap<A, B>()
.ForMember(dest => dest.B1, opt => opt.MapFrom(src => src.A1));
}
private void CreateBToAMapping()
{
this.CreateMap<B, A>()
.ForMember(dest => dest.A1, opt => opt.MapFrom(src => src.B1));;
}
}
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Add the nuget package AutoMapper.Extensions.Microsoft.DependencyInjection |
| Startup.cs
|
public void ConfigureServices(IServiceCollection services)
{
// add as parameter one type for each assembly
services.AddAutoMapper(typeof(ProfileTypeFromAssembly1), typeof(ProfileTypeFromAssembly2));
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Exemple
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var config = new MapperConfiguration(cfg =>
{
cfg.CreateMap<A, B>()
.ForMember(dst => dst.Q2, opts => opts.MapFrom(src => src.P2)); // map A.P2 → B.Q2
.ReverseMap(); // map B → A
});
IMapper mapper = config.CreateMapper();
C c = new C() { P1 = 3 };
A a = new A() { P1 = 1, C1 = c };
B b = mapper.Map<B>(a);
// b.P1 = 1, b.Q2 = 2, b.C1P1 = 3
class A
{
public int P1 { get; set; }
public int P2 { get; set; }
public C C1 { get; set; }
}
class B
{
public int P1 { get; set; } // mapping par convention avec A.P1
public int Q2 { get; set; } // mapping par configuration avec A.P2
public int C1P1 { get; set; } // mapping par flattening avec A.C1.P1
}
class C
{
public int P1 { get; set; }
}
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If the mapping has not been configured, you will get an AutoMapper.AutoMapperMappingException |
List and polymorphism
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// avec une liste
List<B> listB = Mapper.Map<List<A>, List<B>>(listA);
// polymorphism
cfg.CreateMap<Parent1, Parent2>()
.Include<Child1, Child2>();
// IncludeAllDerived(); to include all the derived classes
// without the include, the resulting list contains only Parent2 objects (no Child2 objects)
cfg.CreateMap<Child1, Child2>();
var lp1 = new List<Parent1> { new Parent1 { P1 = 1}, new Child1 { P1 = 2, P2 = 22 } };
var lp2 = mapper.Map<List<Parent2>>(lp1);
// Parent2, Child2
class Parent1
{
public int P1 { get; set; }
}
class Child1 : Parent1
{
public int P2 { get; set; }
}
class Parent2
{
public int P1 { get; set; }
}
class Child2 : Parent2
{
public int P2 { get; set; }
}
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var config = new MapperConfiguration(cfg =>
{
cfg.CreateMap<A, B>()
.ForMember(dest => dest.P1,
opt => opt.MapFrom((src, dest, destMember, resContext) => src.P1 + (int)resContext.Items["+"]));
});
IMapper mapper = config.CreateMapper();
var a = new A { P1 = 1 };
var b = mapper.Map<B>(a, opt => opt.Items["+"] = 9);
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Map 1 object to multiple objects
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var config = new MapperConfiguration(cfg =>
{
// mappings used in the converter
cfg.CreateMap<int, FlatD>()
.ForMember(dest => dest.Id, opt => opt.MapFrom(src => src));
cfg.CreateMap<D, FlatD>();
// main mapping using a converter
cfg.CreateMap<D, IEnumerable<FlatD>>()
.ConvertUsing<DToFlatDConverter>();
});
IMapper mapper = config.CreateMapper();
var d = new D
{
Name = "D",
Ids = { 1, 2, 3 }
};
var flatDs = mapper.Map<IEnumerable<FlatD>>(d).ToList();
// use a converter to flatten D to FlatD
class DToFlatDConverter : ITypeConverter<D, IEnumerable<FlatD>>
{
public IEnumerable<FlatD> Convert(
D source,
IEnumerable<FlatD> destination,
ResolutionContext context)
{
foreach (var id in source.Ids)
{
// use a mapping from int to FlatD to fill the id
var flatD = context.Mapper.Map<FlatD>(id);
// use a mapping from D to FlatD to fill the Name
context.Mapper.Map(source, flatD);
yield return flatD;
}
}
}
class D
{
public string Name { get; set; }
public ICollection<int> Ids { get; } = new List<int>();
}
class FlatD
{
public string Name { get; set; }
public int Id { get; set; }
}
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var mapperMock = new Mock<IMapper>();
mapperMock.Setup(x => x.Map<ItemDto>(It.IsAny<Item>()))
.Returns(new ItemDto());
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Installation
NuGet → AutoMapper
ASP.NET Core
NuGet → AutoMapper.Extensions.Microsoft.DependencyInjection
| Startup.cs
|
public void ConfigureServices(IServiceCollection services)
{
services.AddAutoMapper();
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| MyController.cs
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private readonly IMapper _mapper;
public MyController(IMapper mapper)
{
_mapper = mapper;
B b = _mapper.Map<A, B>(a);
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Configuration dans Profile
