Dernière version du 26 novembre 2024 à 15:43

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

Getting Started
Static and Instance API
AutoMapper.Collection bibliothèque externe pour géré les collections
Map 1 object to list of objects

Setup and configuration

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.AddMaps(typeof(ContainerConfig).Assembly);
});

IMapper mapper = config.CreateMapper();
IMapper mapper = new Mapper(config);

Configuration

Profile

AProfile.cs

internal sealed class AProfile : Profile
{
    public AProfile()
    {
        CreateMap<A, B>()
            .ForMember(dest => dest.B1, opt => opt.MapFrom(src => src.A1));

        CreateMap<B, A>()
            .ForMember(dest => dest.A1, opt => opt.MapFrom(src => src.B1));
            .ForAllOtherMembers(opt => opt.Ignore()); // ignore all other members

        CreateMap<A, C[]>()
            .ConvertUsing<AToCsConverter>();
    }
}

public class AToCsConverter : ITypeConverter<A, C[]>
{
    public C[] Convert(A source, C[] destination, ResolutionContext context)
    {
        return new C[];
    }
}

Dependency Injection

Program.cs

appBuilder.Services.AddAutoMapper(typeof(Program));

Controllers/ItemController.cs

private readonly IMapper mapper;

public ItemController(IMapper mapper)
{
    this.mapper = mapper;
}

AutoMapper 12-

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
    // if all the profiles are in the current assembly
    services.AddAutoMapper(typeof(Startup));

    // add as parameter one type for each assembly
    services.AddAutoMapper(typeof(ProfileTypeFromAssembly1), typeof(ProfileTypeFromAssembly2));

Controllers/ItemController.cs

private readonly IMapper mapper;

public ItemController(ItemDbContext context, IMapper mapper)
{
    this.mapper = mapper;
}

WPF

App.xaml.cs

protected override void RegisterTypes(IContainerRegistry containerRegistry)
{
    var config = new MapperConfiguration(cfg =>
    {
        cfg.AddMaps(typeof(App).Assembly);
    });

    containerRegistry.RegisterSingleton<IMapper>(() => config.CreateMapper());
}

Exemple

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; }
}

Flattening

Flattening

var config = new MapperConfiguration(cfg =>
{
    // default flattening
    // naming convention:    SpecificItem.Category   → SpecificItemDto.Category 
    // flatening conventing: SpecificItem.Item.Id    → SpecificItemDto.ItemId
    // configuration:        SpecificItem.Item.Code  → SpecificItemDto.Code
    cfg.CreateMap<SpecificItem, SpecificItemDto>()
       .ForMember(dest => dest.Code, opt => opt.MapFrom(src => src.Item.Code));

    // flattening from composition to inheritance
    // naming convention:    SpecificItem.Category   → SpecificItemDtoV2.Category
    // configuration: explicitly call the mapping of Item → SpecificItemDtoV2 for the Item property
    cfg.CreateMap<SpecificItem, SpecificItemDtoV2>()
       .IncludeMembers(x => x.Item);
    // naming convention: Item.Id   → ItemDtoV2.Id
    // naming convention: Item.Code → ItemDtoV2.Code
    cfg.CreateMap<Item, ItemDtoV2>();
    // MemberList.None to skip validation and ignore unmapped destination properties like Category
    cfg.CreateMap<Item, SpecificItemDtoV2>(MemberList.None)
       .IncludeBase<Item, ItemDtoV2>();
});

config.AssertConfigurationIsValid();
IMapper mapper = config.CreateMapper();

var specificItem = new SpecificItem
{
    Item = new Item
    {
        Id = 1,
        Code = 2
    },
    Category = 3
};

var specificItemDto = mapper.Map<SpecificItemDto>(specificItem);

var specificItemDtoV2 = mapper.Map<SpecificItemDtoV2>(specificItem);

// source
class Item
{
    public int Id { get; set; }
    public int Code { get; set; }
}

class SpecificItem
{
    public int Category { get; set; }
    public Item Item { get; set; }
}

// destination
class SpecificItemDto
{
    public int ItemId { get; set; }
    public int Code { get; set; }
    public int Category { get; set; }
}

class ItemDtoV2
{
    public int Id { get; set; }
    public int Code { get; set; }
}

class SpecificItemDtoV2 : ItemDtoV2
{
    public int Category { get; set; }
}

Unflattening

// unflattening UserDto.GroupId → User.Group.Id
this.CreateMap<UserDto, User>()
    .ForPath(dest => dest.Group.Id, opt => opt.MapFrom(src => src.GroupId));

List and polymorphism

// 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; }
}

Mapping Inheritance

Pass parameter to the mapping

var config = new MapperConfiguration(cfg =>
{
    cfg.CreateMap<A, B>()
        .ForMember(dest => dest.P1,
            opt => opt.MapFrom((src, _, _, context) => src.P1 + (int)context.Items["+"]));
});

IMapper mapper = config.CreateMapper();

var a = new A { P1 = 1 };
var b = mapper.Map<B>(a, opt => opt.Items["+"] = 9);

Map 1 object to multiple objects

// map 1 Group to many User

class Group
{
    public int Id { get; set; }
    public ICollection<int> UserIds { get; } = new List<int>();
}

class User
{
    public int Id { get; set; }
    public int GroupId { get; set; }
}

Flatten to ValueType

var config = new MapperConfiguration(cfg =>
{
    cfg.CreateMap<(Group group, int userId), User>()
        .IncludeMembers(s => s.group)  // call the mapping Group → User
        .ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.userId));

    cfg.CreateMap<Group, User>()
        .ForMember(dest => dest.GroupId, opt => opt.MapFrom(src => src.Id))
        .ForMember(dest => dest.Id, opt => opt.Ignore());
});

IMapper mapper = config.CreateMapper();

var group = new Group
{
    Id = 9,
    UserIds = {1, 2, 3}
};

IEnumerable<(int groupId, int userId)> groupAndUserList = group.UserIds.Select(x => ValueTuple.Create(group.Id, x));
var users = mapper.Map<IEnumerable<User>>(groupAndUserList).ToList();

Flatten with a ITypeConverter

var config = new MapperConfiguration(cfg =>
{
    cfg.CreateMap<int, User>()
        .ForMember(dest => dest.Id, opt => opt.MapFrom(src => src));

    cfg.CreateMap<Group, User>()
        .ForMember(dest => dest.GroupId, opt => opt.MapFrom(src => src.Id))
        .ForMember(dest => dest.Id, opt => opt.Ignore());

    cfg.CreateMap<Group, IEnumerable<User>>()
        .ConvertUsing<GroupToUsersConverter>();
});

IMapper mapper = config.CreateMapper();

var group = new Group
{
    Id = 9,
    UserIds = { 1, 2, 3 }
};
var users = mapper.Map<IEnumerable<User>>(group).ToList();

// use a converter to flatten a Group
class GroupToUsersConverter : ITypeConverter<Group, IEnumerable<User>>
{
    public IEnumerable<User> Convert(
        Group source,
        IEnumerable<User> destination,
        ResolutionContext context)
    {
        foreach (var userId in source.UserIds)
        {
            var user = context.Mapper.Map<User>(userId);
            context.Mapper.Map(source, user);

            yield return user;
        }
    }
}

Conditional mapping

cfg.CreateMap<A, B>()
   // map A.P2 → B.Q2 if A.P2 > 0
   // if A.P2 <= 0 → B.Q2 = 0
   .ForMember(dest => dest.Q2,
              opt =>
              {
                  opt.Condition(src => src.P2 > 0);
                  opt.MapFrom(src => src.P2);
              });

Before and After Map Action

cfg.CreateMap<A, B>()
   .BeforeMap((src, dest) => src.P1 += 1)
   .AfterMap((src, dest) => dest.P1 -= 1);

Inject a dependency during the mapping with a ValueResolver

Program.cs

// UserProvider is injected as a dependency, and AutoMapper has to be injected as a dependency too
appBuilder.Services.AddScoped<IUserProvider, UserProvider>()
                   .AddAutoMapper(typeof(AProfile));

AProfile.cs

public class AProfile : Profile
{
    public AProfile()
    {
        this.CreateMap<A, B>()
            .ForMember(x => x.User, opt => opt.MapFrom<UserValueResolver>());
    }
}

// UserProvider is retrieved as a dependency and used to resolve the mapping
public class UserValueResolver(IUserProvider userProvider) : IValueResolver<A, B, User>
{
    public User Resolve(A source, B destination, User member, ResolutionContext context)
    {
        return userProvider.GetUser();
    }
}

Errors

A lambda expression with a statement body cannot be converted to an expression tree

this.CreateMap<Class1, Class2>()
    .ForMember(dest => dest.Prop1, opt => opt.MapFrom(src =>
    {
        // ...
    }));

// use a new overload of MapFrom
this.CreateMap<Class1, Class2>()
    .ForMember(dest => dest.Prop1, opt => opt.MapFrom((src, dest) =>
    {
        // ...
    }));

MOQ

var mapperMock = new Mock<IMapper>();
mapperMock.Setup(x => x.Map<ItemDto>(It.IsAny<Item>()))
          .Returns(new ItemDto());

Unit tests

MyProfileTests.cs

public class MyProfileTests
{
    private readonly Fixture fixture;
    private readonly MapperConfiguration configuration;
    private readonly IMapper mapper;

    public MyProfileTests()
    {
        fixture = new();
        configuration = new MapperConfiguration(cfg => cfg.AddProfile<MyProfile>());
        mapper = configuration.CreateMapper();
    }

    [Fact]
    public void MyProfile_IsValid()
        => configuration.AssertConfigurationIsValid();

    [Fact]
    public void Map_SourceToDestination_ShouldMapCorrectly()
    {
        // Arrange
        var source = fixture.Create<MySource>();

        // Act
        var destination = mapper.Map<MyDestination>(source);

        // Assert
        Assert.NotNull(destination);
        Assert.Equal(source.Property1, destination.Property1);
    }

Dependency Injection

The ctor of MyValueResolver take a parameter of type IMyService.
So to test the profile, you have to inject IMyService to resolve MyValueResolver.

MyProfileTests.cs

public class MyProfileTests
{
    private readonly Fixture fixture;
    private readonly IMapper mapper;

    public MyProfileTests()
    {
        mockMyService = new Mock<IMyService>();
        mockApplicationUserProvider
            .Setup(x => x.GetData())
            .Returns(fixture.Create<Data>());

        var serviceProvider = new ServiceCollection()
            .AddSingleton(mockMyService.Object)
            .AddSingleton<MyValueResolver>()
            .AddAutoMapper(cfg => cfg.AddProfile<MyProfile>())
            .BuildServiceProvider();

        mapper = serviceProvider.GetRequiredService<IMapper>();
    }

Mock the mapper

// create a mock mapper
var mockMapper = new Mock<IMapper>();
// mock the mapping
this.mockMapper.Setup(x => x.Map<MyDto>(It.IsAny<MyEntity>()))
               .Returns(myDto);

// or create a new simplified mapper
var mapper = new Mapper(
    new MapperConfiguration(
        cfg =>
        {
            cfg.CreateMap<MyEntity, MyDto>()
               .ForMember(dest => dest.Property1, opt => opt.Ignore());
        }));

Installation

NuGet → AutoMapper

ASP.NET Core

NuGet → AutoMapper.Extensions.Microsoft.DependencyInjection

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
    services.AddAutoMapper(typeof(Startup));

MyController.cs

private readonly IMapper mapper;

public MyController(IMapper mapper)
{
    this.mapper = mapper;

    B b = this.mapper.Map<A, B>(a);

Configuration dans Profile

« Automapper » : différence entre les versions

Dernière version du 26 novembre 2024 à 15:43

Sommaire

Description

Liens

Setup and configuration

Profile

Dependency Injection

AutoMapper 12-

WPF

Exemple

Flattening

Unflattening

List and polymorphism

Pass parameter to the mapping

Map 1 object to multiple objects

Flatten to ValueType

Flatten with a ITypeConverter

Conditional mapping

Before and After Map Action

Inject a dependency during the mapping with a ValueResolver

Errors

A lambda expression with a statement body cannot be converted to an expression tree

MOQ

Unit tests

Dependency Injection

Mock the mapper

Installation

ASP.NET Core

Actions de la page

Actions de la page

Outils personnels

Menu de navigation

Navigation

Rechercher

Outils

« Automapper » : différence entre les versions

Dernière version du 26 novembre 2024 à 15:43

Description

Liens

AutoMapper 12-

WPF

Exemple

Unflattening

List and polymorphism

Map 1 object to multiple objects

Flatten to ValueType

Flatten with a ITypeConverter

Inject a dependency during the mapping with a ValueResolver

Errors

Dependency Injection

Mock the mapper

Installation

ASP.NET Core

Menu de navigation

Rechercher

« Automapper » : différence entre les versions