How to add AutoMapper to DI in .Net core 2.0 Conso

问题:

I try to use AutoMapper in my .Net Core 2.0 Console Application. My class looks like this:

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

I tried to add services into Main method:

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

But I have the next error 'One or more errors occurred. (Object reference not set to an instance of an object.)'

Please tell me how to add AutoMapper to use DI.

回答1:

You need to add this nuget package AutoMapper.Extensions.Microsoft.DependencyInjection to your project and add AutoMapper to your ServiceCollection like this

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

回答2:

Install the 'AutoMapper' and 'Microsoft.Extensions.DependencyInjection' package from NuGet.

Implement User and UserDTO class for mapping from User to UserDTO:

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; }
}

Implement an interface and a class for doing Mapping operation as follows(don't forget using 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;
    }
}

After that create a RegisterServices method for doing Dependency Injection in your project and a DisposeServices method for disposing of the service provider.

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();
           }
        }
    }
}

Good Luck

回答3:

You need to map a concrete class that implements IMapper. I followed Automapper documentation and it worked fine, it would be more efficient to show their documentation than writing you code there and I don't want copy / paste their sample

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

But it would be like this: services.AddTransient<IMapper,YourconcreteClass>();