在我的Startup.cs (Core 2.2, Automapper 8.1.1)

services.AddAutoMapper(new Type[] { typeof(DAL.MapperProfile) });            

在我的数据访问项目中

namespace DAL
{
    public class MapperProfile : Profile
    {
        // place holder for AddAutoMapper (to bring in the DAL assembly)
    }
}

在模型定义中

namespace DAL.Models
{
    public class PositionProfile : Profile
    {
        public PositionProfile()
        {
            CreateMap<Position, PositionDto_v1>();
        }
    }

    public class Position
    {
        ...
    }

需要安装一个安装自动程序的包。

添加AutoMapper.Extensions.Microsoft.DependencyInjection包

之后AddAutoMapper将在服务中可用。

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

创建从Employee类到EmployeeDTO的映射器。

using AutoMapper;

public class AutomapperProfile: Profile
{
    public AutomapperProfile()
    {
        //Source to destination.
        CreateMap<Employee,EmployeeDTO>();
    }
}

EmployeeController从Employee映射到EmployeeDTo

using System.Collections.Generic;
using AutoMapper;
using Microsoft.AspNetCore.Mvc;

[Route("api/[controller]")]
[ApiController()]
public class EmployeeController : ControllerBase
{
    private readonly IMapper _mapper;

    public EmployeeController(IMapper mapper)
    {
        _mapper = mapper;
    }

    [HttpGet]
    public IEnumerable<EmployeeDTO> GetEmployees()
    {
        /* 
        Assume it to be a  service call/database call
        it returns a list of employee, and now we will map it to EmployeeDTO
        */
        var employees = Employee.SetupEmployee();
        var employeeDTO = _mapper.Map<IEnumerable<EmployeeDTO>>(employees);
        return employeeDTO;

    }
}

Employee.cs供参考

using System.Collections.Generic;

public class Employee
{
    public int EmployeeId { get; set; }
    public string EmployeeName { get; set; }
    public int Salary { get; set; }

    public static IEnumerable<Employee> SetupEmployee()
    {
        return new List<Employee>()
        {
            new Employee(){EmployeeId = 1, EmployeeName ="First", Salary=10000},
            new Employee(){EmployeeId = 2, EmployeeName ="Second", Salary=20000},
            new Employee(){EmployeeId = 3, EmployeeName ="Third", Salary=30000},
            new Employee(){EmployeeId = 4, EmployeeName ="Fourth", Salary=40000},
            new Employee(){EmployeeId = 5, EmployeeName ="Fifth", Salary=50000}
        };
    }

}

EmployeeDTO.cs供参考

public class EmployeeDTO
{
    public int EmployeeId { get; set; }
    public string EmployeeName { get; set; }
}

在最新版本的asp.net core中，你应该使用以下初始化:

services.AddAutoMapper(typeof(YourMappingProfileClass));

我使用的是AutoMapper 6.1.1和asp.net Core 1.1.2。

首先，定义由Automapper的Profile Class继承的Profile类。我创建了IProfile接口，该接口为空，目的只是为了查找该类型的类。

 public class UserProfile : Profile, IProfile
    {
        public UserProfile()
        {
            CreateMap<User, UserModel>();
            CreateMap<UserModel, User>();
        }
    }

现在创建一个单独的类，例如Mappings

 public class Mappings
    {
     public static void RegisterMappings()
     {            
       var all =
       Assembly
          .GetEntryAssembly()
          .GetReferencedAssemblies()
          .Select(Assembly.Load)
          .SelectMany(x => x.DefinedTypes)
          .Where(type => typeof(IProfile).GetTypeInfo().IsAssignableFrom(type.AsType()));

            foreach (var ti in all)
            {
                var t = ti.AsType();
                if (t.Equals(typeof(IProfile)))
                {
                    Mapper.Initialize(cfg =>
                    {
                        cfg.AddProfiles(t); // Initialise each Profile classe
                    });
                }
            }         
        }

    }

现在在MVC核心web项目的Startup.cs文件中，在构造函数中，调用Mapping类，它将在应用程序时初始化所有映射 装载。

Mappings.RegisterMappings();

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。

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);