Question

我尝试在.Net Core 2.0控制台应用程序中使用AutoMapper。我的班级看起来像这样：

public class AutoGetCurrency
{
    private readonly IMapper mapper;
    public AutoGetCurrency(IMapper mapper) {
    this.mapper = mapper;
    }
    ....
}

我尝试将服务添加到主方法中：

static void Main(string[] args)
{
    var services = new ServiceCollection();
    ServiceProvider = services.BuildServiceProvider();
    services.AddTransient<IMapper>();
    ....
}

但我有下一个错误＆＃39;发生了一个或多个错误。（对象引用未设置为对象的实例。）＆＃39;

请告诉我如何添加AutoMapper以使用DI。

Answer 1

您需要将此nuget包AutoMapper.Extensions.Microsoft.DependencyInjection添加到您的项目中，并将AutoMapper添加到ServiceCollection这样的

var services = new ServiceCollection();
services.AddAutoMapper(mapperConfig => mapperConfig.AddProfiles(GetType().Assembly))
ServiceProvider = services.BuildServiceProvider();

Answer 2

从NuGet安装'AutoMapper'和'Microsoft.Extensions.DependencyInjection'程序包。

实现用于从User到UserDTO映射的User和UserDTO类：

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
}
public class UserDTO
{
    public int Id { get; set; }
    public string Name { get; set; }
}

实现如下接口和用于进行Mapping操作的类（不要忘记使用AutoMapper）：

public interface ICustomMapper<T>
{
    T MapUserToUserDTO();
}
public class CustomMapper : ICustomMapper<UserDTO>
{
    private readonly IMapper mapper;
    public CustomMapper(IMapper mapper) =>
        this.mapper = mapper;
    public UserDTO MapUserToUserDTO()
    {
        User user = new User()
        {
           Id = 5,
           Name = "Iman"
        };
        UserDTO userDTO = mapper.Map<UserDTO>(user);
        return userDTO;
    }
}

之后，创建一个RegisterServices方法以在项目中进行依赖注入，并创建一个DisposeServices方法以处理服务提供者。

using AutoMapper;
using Microsoft.Extensions.DependencyInjection;

namespace AutoMapperProject
{
    class Program
    {
        private static IServiceProvider _serviceProvider;
        static void Main(string[] args)
        {
            RegisterServices();
            ICustomMapper<UserDTO> service = 
            _serviceProvider.GetService<ICustomMapper<UserDTO>>();
            UserDTO userDTO = service.MapUserToUserDTO();
            DisposeServices();
            Console.WriteLine("Hello AutoMapper!");
        }
        private static void RegisterServices()
        {
            var collection = new ServiceCollection();
            collection.AddAutoMapper(typeof(Program));
            collection.AddScoped<ICustomMapper<UserDTO>, CustomMapper>();
            // ...
            // Add other services
            // ...
            _serviceProvider = collection.BuildServiceProvider();
        }
        private static void DisposeServices()
        {
           if (_serviceProvider == null)
           {
              return;
           }
           if (_serviceProvider is IDisposable)
           {
              ((IDisposable)_serviceProvider).Dispose();
           }
        }
    }
}

祝你好运

Answer 3

您需要映射实现IMapper的具体类。我遵循Automapper文档，它工作正常，显示他们的文档比在那里编写代码更有效，我不想复制/粘贴他们的样本

http://automapper.readthedocs.io/en/latest/Dependency-injection.html

但它会是这样的：services.AddTransient<IMapper,YourconcreteClass>();

如何在.Net core 2.0控制台应用程序中将AutoMapper添加到DI

3 个答案: