c# - 将依赖项注入(inject) .net 核心中的自动映射器配置文件 - IHttpContextAccessor 返回 null

Question

目标:将 IHttpContextAccessor 作为依赖注入(inject)到 autmapper 配置文件的构造函数中

原因:我需要传入当前用户的身份名称作为构建我的域对象之一的一部分

问题获取到的User身份始终为null

到目前为止我有什么？

Startup.cs

mc.AddProfile(new DtoToOtherProfile(new HttpContextAccessor()));

//OR

var mapperConfiguration = new MapperConfiguration(mc =>
        {
            IServiceProvider provider = services.BuildServiceProvider();
            mc.AddProfile(new DtoToOtherProfile(provider.GetService<IHttpContextAccessor>()));
        });

DtoToOtherProfile.cs

 public DtoToOtherProfile(IHttpContextAccessor httpContextAccessor)
    {
     _httpContextAccessor = httpContextAccessor;

     CreateMap<MyDto, MyOther>()
    .ConstructUsing(myDto => new myOther(myDto.prop1, myDto .prop2,  _httpContextAccessor.HttpContext.User.Identity.Name)); // the name is what i intend to pass
      // other mapping
    }

Controller.cs

  public async Task<IActionResult> Create([FromBody]MyDto model)
    {
        if (!ModelState.IsValid)
        {
            return BadRequest(ModelState);
        }

        // save campaign
        var myOtherModel = _mapper.Map<MyOther>(model);
        // myOtherModel.UserName is always null 
       // rest
      }

有什么东西不见了吗？请指点？

Answer 1

我认为正确的做法不是在 Profile 中注入(inject) IHttpContextAccessor 而是创建一个单独的 IValueResolver 并在那里注入(inject) IHttpContextAccessor。所以只需执行以下操作，我想在其中获取用户对 httpcontext 的声明

在你的StartUp.cs里面ConfigureServices添加

 services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
 services.AddAutoMapper();

使用您的映射创建配置文件

public class MappingProfile : Profile
    {
        public MappingProfile()
        {
            CreateMap<QueryUniqueDto, QueryUnique>()
                .ForMember(s=>s.UserClaim,opt=>opt.MapFrom<IdentityResolver>());
        }
    }

创建IValueResolver

public class IdentityResolver : IValueResolver<QueryUniqueDto, QueryUnique, UserClaim>
  {
    private IHttpContextAccessor _httpContextAccessor;

    public IdentityResolver(IHttpContextAccessor httpContextAccessor) 
    {
      _httpContextAccessor = httpContextAccessor;
    }

    public UserClaim Resolve(QueryUniqueDto source, QueryUnique destination, UserClaim destMember, ResolutionContext context)
    {
        return Helper.GetClaimsFromUser(_httpContextAccessor.HttpContext?.User.Identity as ClaimsIdentity);
    }
  }

这太棒了!!!