我喜欢很多答案，尤其是@saineshwar的答案。我使用的是。net Core 3.0和AutoMapper 9.0，所以我觉得是时候更新答案了。

对我有用的是在Startup.ConfigureServices(…)中以这样的方式注册服务:

    services.AddAutoMapper(cfg => cfg.AddProfile<MappingProfile>(), 
                               AppDomain.CurrentDomain.GetAssemblies());

我认为@saineshwar的其余答案保持完美。但如果有人感兴趣，我的控制器代码是:

[HttpGet("{id}")]
public async Task<ActionResult> GetIic(int id)
{
    // _context is a DB provider
    var Iic = await _context.Find(id).ConfigureAwait(false);

    if (Iic == null)
    {
        return NotFound();
    }

    var map = _mapper.Map<IicVM>(Iic);

    return Ok(map);
}

我的映射类:

public class MappingProfile : Profile
{
    public MappingProfile()
    {
        CreateMap<Iic, IicVM>()
            .ForMember(dest => dest.DepartmentName, o => o.MapFrom(src => src.Department.Name))
            .ForMember(dest => dest.PortfolioTypeName, o => o.MapFrom(src => src.PortfolioType.Name));
            //.ReverseMap();
    }
}

-----编辑-----

在阅读了Lucian Bargaoanu评论中的文档链接后，我认为最好稍微改变一下这个答案。

无参数services.AddAutoMapper()(具有@saineshwar答案)不再工作(至少对我来说)。但是如果你使用NuGet程序集AutoMapper.Extensions.Microsoft。DependencyInjection，框架能够检查所有扩展AutoMapper的类。配置文件(像我的，MappingProfile)。

因此，在我的例子中，类属于同一个正在执行的程序集，服务注册可以缩短为services.AddAutoMapper(System.Reflection.Assembly.GetExecutingAssembly()); (一种更优雅的方法是使用这种编码的无参数扩展)。

谢谢,卢西恩!

让我们来看看如何将Auto mapper添加到。net Core应用程序中。

步骤:1 第一步是安装相应的NuGet包:

Install-Package AutoMapper.Extensions.Microsoft.DependencyInjection

一步:2

安装所需的包后，下一步是配置服务。让我们在Startup.cs类中执行:

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

一步:3

让我们开始使用，我们有一个名为User的域对象:

public class User
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { get; set; }
    public string Address { get; set; }
}

在UI层，我们将有一个视图模型来显示用户信息:

public class UserViewModel
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { get; set; }
}

一步:4

组织映射配置的一个好方法是使用Profiles。我们需要创建从Profile类继承的类，并将配置放在构造函数中:

public UserProfile()
{
    CreateMap<User, UserViewModel>();
}

一步:5

现在，让我们定义一个Controller并使用我们刚刚添加的Auto-Mapping功能:

public class UserController : Controller
{
    private readonly IMapper _mapper;
    public UserController(IMapper mapper)
    {
        _mapper = mapper;
    }
    public IActionResult Index()
    {
        // Populate the user details from DB
        var user = GetUserDetails();
        UserViewModel userViewModel = _mapper.Map<UserViewModel>(user);
        return View(userViewModel);
    }
}

首先，我们将映射器对象注入到控制器中。然后，我们调用Map()方法，它将User对象映射到UserViewModel对象。此外，请注意我们用于本地数据存储的本地方法GetUserDetails。 您可以在我们的源代码中找到它的实现。

ASP。NET Core(使用2.0+和3.0测试)，如果你喜欢阅读源文档: https://github.com/AutoMapper/AutoMapper.Extensions.Microsoft.DependencyInjection/blob/master/README.md

否则，遵循以下4个步骤即可:

从nuget安装AutoMapper.Extensions.Microsoft.DependancyInjection。 只需添加一些概要文件类。 然后将以下内容添加到你的startup.cs类中。 services.AddAutoMapper (OneOfYourProfileClassNamesHere) 然后简单地在你的控制器或任何你需要它的地方注入IMapper:

public class EmployeesController {

    private readonly IMapper _mapper;

    public EmployeesController(IMapper mapper){

        _mapper = mapper;
    }

如果你想使用ProjectTo，现在很简单:

var customers = await dbContext.Customers.ProjectTo<CustomerDto>(_mapper.ConfigurationProvider).ToListAsync()

我想明白了!细节如下:

Add the main AutoMapper Package to your solution via NuGet. Add the AutoMapper Dependency Injection Package to your solution via NuGet. Create a new class for a mapping profile. (I made a class in the main solution directory called MappingProfile.cs and add the following code.) I'll use a User and UserDto object as an example. public class MappingProfile : Profile { public MappingProfile() { // Add as many of these lines as you need to map your objects CreateMap<User, UserDto>(); CreateMap<UserDto, User>(); } } Then add the AutoMapperConfiguration in the Startup.cs as shown below: public void ConfigureServices(IServiceCollection services) { // .... Ignore code before this // Auto Mapper Configurations var mapperConfig = new MapperConfiguration(mc => { mc.AddProfile(new MappingProfile()); }); IMapper mapper = mapperConfig.CreateMapper(); services.AddSingleton(mapper); services.AddMvc(); } To invoke the mapped object in code, do something like the following: public class UserController : Controller { // Create a field to store the mapper object private readonly IMapper _mapper; // Assign the object in the constructor for dependency injection public UserController(IMapper mapper) { _mapper = mapper; } public async Task<IActionResult> Edit(string id) { // Instantiate source object // (Get it from the database or whatever your code calls for) var user = await _context.Users .SingleOrDefaultAsync(u => u.Id == id); // Instantiate the mapped data transfer object // using the mapper you stored in the private field. // The type of the source object is the first type argument // and the type of the destination is the second. // Pass the source object you just instantiated above // as the argument to the _mapper.Map<>() method. var model = _mapper.Map<UserDto>(user); // .... Do whatever you want after that! } }

对于使用。net 7的AutoMapper 11.0.1，我开始得到这个异常:

System.ArgumentException: 'GenericArguments[0], 'System.DateTime', on 'T MaxInteger[T](System.Collections.Generic.IEnumerable`1[T])' violates the constraint of type 'T'.'

Inner Exception
VerificationException: Method System.Linq.Enumerable.MaxInteger: type argument 'System.DateTime' violates the constraint of type parameter 'T'.

看这个问题:

系统。DateTime on 'T MaxInteger[T](System.Collections.Generic.IEnumerable ' 1[T])'违反了。net 7使用AutoMapper 11.0.1的T类型约束

这意味着我不能再使用services.AddAutoMapper(typeof(MappingProfile).Assembly);无一例外。

对于AutoMapper.Extensions.Microsoft.DependencyInjection我这样解决它:

services.AddAutoMapper(cfg => cfg.Internal().MethodMappingEnabled = false, typeof(MappingProfile).Assembly);

对于Blazor WebAssembly客户端，解决方案是这样的:

var mapperConfig = new MapperConfiguration(mc =>
{
    //Needed for https://github.com/AutoMapper/AutoMapper/issues/3988
    mc.Internal().MethodMappingEnabled = false;
    mc.AddProfile(new MappingProfile());
});
//mapperConfig.AssertConfigurationIsValid();

IMapper mapper = mapperConfig.CreateMapper();
builder.Services.AddSingleton(mapper);

theutz的回答很好，我只想补充一点:

如果你让你的映射配置文件继承自MapperConfigurationExpression而不是profile，你可以非常简单地添加一个测试来验证你的映射设置，这总是很方便:

[Fact]
public void MappingProfile_VerifyMappings()
{
    var mappingProfile = new MappingProfile();

    var config = new MapperConfiguration(mappingProfile);
    var mapper = new Mapper(config);

    (mapper as IMapper).ConfigurationProvider.AssertConfigurationIsValid();
}