首先，通过 NuGet 安装 AutoMapper 的依赖包：

AutoMapper.Extensions.Microsoft.DependencyInjection

这是需要转换的模型类：

namespace Blog.Model.Entities {
    public class Post {
        public int Id { get; set; }
        public string Title { get; set; }
        public string CoverImage { get; set; }
        public string Content { get; set; }
        public string Category { get; set; }
        public int Views { get; set; }
        public DateTime CreatedAt { get; set; }
        public int CreatorId { get; set; }
    }
}

接下来定义一个数据传输对象（DTO）类：

public class PostDto {
    public int Id { get; set; }
    public string Title { get; set; }
    public string CoverImage { get; set; }
    public string Content { get; set; }
    public string Category { get; set; }
    public DateTime CreatedAt { get; set; }
    public int CreatorId { get; set; }
    public string CreatorName { get; set; }
    public string Avatar { get; set; }
}

创建 Profile 类来进行对象映射配置：

public class PostProfile : Profile {
    public PostProfile() {
        CreateMap();
        CreateMap();
        CreateMap();
        CreateMap()
            .ForMember(dest => dest.Avatar, opt => opt.MapFrom(src => src.Creator.Avatar))
            .ForMember(dest => dest.CreatorName, opt => opt.MapFrom(src => src.Creator.UserName));
        CreateMap();
    }
}

注册这些 Profile 文件：

public class AutoMapperConfiguration {
    public static MapperConfiguration RegisterProfiles() {
        var config = new MapperConfiguration(cfg => {
            cfg.AddProfile(new PostProfile());
            cfg.AddProfile(new UserProfile());
        });
        return config;
    }
}

为 IServiceCollection 添加扩展方法：

public static class AutoMapperSetupExtensions {
    public static void AddCustomAutoMapper(this IServiceCollection services) {
        if (services == null) throw new ArgumentNullException(nameof(services));
        services.AddAutoMapper(typeof(AutoMapperConfiguration));
    }
}

在 Startup.cs 中使用该扩展方法：

builder.Services.AddCustomAutoMapper();

在控制器中注入并使用 IMapper 接口进行对象映射：

[ApiController]
[Route("api/[controller]")]
public class AuthController : ControllerBase {
    private readonly IMapper _mapper;
    private readonly ILogger<AuthController> _logger;
    private readonly IBaseService<UserInfo> _userService;

    public AuthController(ILogger<AuthController> logger, IMapper mapper, IBaseService<UserInfo> userService) {
        _logger = logger;
        _mapper = mapper;
        _userService = userService;
    }

    [HttpPost("register")]
    public async Task> RegisterAsync(CreateUserInput input) {
        var user = await _userService.FindByCondition(x => x.Username == input.Username);
        if (user != null) {
            return BadRequest(new MessageModel<string> { Success = false, Msg = "用户名已存在" });
        }
        input.Password = MD5Helper.MD5Encrypt32(input.Password);
        user = _mapper.Map<UserInfo>(input);
        await _userService.CreateAsync(user, true);
        return Ok(new MessageModel<string> { Success = true, Msg = "注册成功", Response = GetUserJwt(user) });
    }
}

最后进行功能测试。