Automapper在Profile类

Question

我有以下映射配置文件

public class DomainProfile : Profile
{
    private FootballPredictionsContext m_Context;

    public DomainProfile(FootballPredictionsContext context)
    {
        m_Context = context;
    }

    public DomainProfile()
    {
        CreateMap<TipModel, Tip>()
            .ForMember(tip => tip.BetType, m => m.MapFrom(x => m_Context.BetTypes.First(y => y.Name == x.BetType)))
            .ForMember(tip => tip.BetCategory, m => m.MapFrom(x => m_Context.BetCategories.First(y => y.Name == x.BetCategory)))
            .ForMember(tip => tip.Sport, m => m.MapFrom(x => m_Context.Sports.First(y => y.Name == x.Sport)))
            .ForMember(tip => tip.Tipster, m => m.MapFrom(model => m_Context.Tipsters.First(y => y.Username == model.Tipster)));
    }
}

正如您所看到的，某些映射正在使用DbContext，因此我必须以某种方式将其注入DomainProfile

在Startup类中，我正在初始化Automapper

public void ConfigureServices(IServiceCollection services)
        {
            services.AddScoped(typeof(IUnificator), typeof(Unificator));
            services.AddDbContext<FootballPredictionsContext>(options => options.UseSqlServer(Configuration.GetConnectionString("Database")));
            services.AddDbContext<UnificationContext>(options => options.UseSqlServer(Configuration.GetConnectionString("Database")));

            services.AddSingleton(provider => new MapperConfiguration(cfg =>
                {
                    cfg.AddProfile(new UserProfile(provider.GetService<IUserManager>()));
                }).CreateMapper());
            services.AddMvc();
        }

我尝试了this解决方案，但我收到了'Cannot resolve scoped service 'FootballPredictions.DAL.FootballPredictionsContext' from root provider.'

Answer 1

我最近遇到过类似的问题，这是因为我试图将服务注入到具有更长生命周期的服务（例如，瞬态和范围）。与DomainProfile类相关的生命周期是什么？您是否尝试将其更改为Scoped或Transient以查看是否有帮助？

由@DimitarTsonev实施： 因此，将映射器范围更改为

services.AddScoped(provider => new MapperConfiguration(cfg =>
    {
        cfg.AddProfile(new DomainProfile(provider.GetService<FootballPredictionsContext>()));
    }).CreateMapper());

解决了问题

Answer 2

假设您实际上已经注册了上下文（例如services.AddDbContext），则该异常的最可能原因是您在之前注册了AutoMapper ＆＃ 39;重新注册上下文。在执行services.AddAutoMapper之前，请确保首先注册您的上下文。