c# - Automapper，映射配置不持久

Question

所以问题。

我加了

AutoMapperConfig.Configure();

到global.asax中的application_Start

它运行代码

Mapper.Initialize(x =>
{
  x.AddProfile<DomainToViewModelMappingProfile>();
  x.AddProfile<ViewModelToDomainMappingProfile>();
});

Mapper.AssertConfigurationIsValid();

运行

public class DomainToViewModelMappingProfile : Profile
{
    protected override void Configure()
    {

        Mapper.CreateMap<DBO.User, ViewModels.UserViewModel>();
    }
}

和

public class ViewModelToDomainMappingProfile : Profile
{
    protected override void Configure()
    {
        Mapper.Initialize(cfg =>
        {
            cfg.CreateMap<ViewModels.UserViewModel, DBO.User>();
        });
    }
}

一切都可以正常编译和运行。

但是在 Controller 中:

UserViewModel model = new UserViewModel();
User user = userService.GetUser(2);
model = Mapper.Map<User, UserViewModel>(user); //this line fails as mapping doesnt exist
return View();

但是如果我在 Controller 方法中添加映射配置

Mapper.CreateMap<ViewModels.UserViewModel,DBO.User>();
UserViewModel model = new UserViewModel();
User user = userService.GetUser(2);
model = Mapper.Map<User, UserViewModel>(user); //Works great
return View();

它工作正常。

忽略自动映射器的不同语法。我尝试了已弃用的和新的映射方式，但都失败了。

谢谢

Answer 1

问题是您在 Profile 中调用 Initialize 方法，这会导致覆盖您已经存在的映射:

public class ViewModelToDomainMappingProfile : Profile
{
    protected override void Configure()
    {
        // you should not to call Initialize method inside your profiles.
        Mapper.Initialize(cfg =>
        {
            cfg.CreateMap<ViewModels.UserViewModel, DBO.User>();
        });
    }
}

在这里，你有两种方式:

方式 #1(使用静态 API - 已弃用)

public class DomainToViewModelMappingProfile : Profile
{
    protected override void Configure()
    {
        Mapper.CreateMap<DBO.User, ViewModels.UserViewModel>();
    }
}

public class ViewModelToDomainMappingProfile : Profile
{
    protected override void Configure()
    {
        Mapper.CreateMap<ViewModels.UserViewModel, DBO.User>();
    }
}

// initialize your mapper by provided profiles
Mapper.Initialize(x =>
{
  x.AddProfile<DomainToViewModelMappingProfile>();
  x.AddProfile<ViewModelToDomainMappingProfile>();
});

Mapper.AssertConfigurationIsValid();

方式 #2(使用实例 API)

// in this case just call CreateMap from Profile class - its the same as CreateMap on `cfg`
public class DomainToViewModelMappingProfile : Profile
{
    public DomainToViewModelMappingProfile()
    {
        CreateMap<DBO.User, ViewModels.UserViewModel>();
    }
}

public class ViewModelToDomainMappingProfile : Profile
{
    public ViewModelToDomainMappingProfile()
    {
        CreateMap<ViewModels.UserViewModel, DBO.User>();
    }
}

// initialize you mapper config
var config = new MapperConfiguration(cfg => {
    cfg.AddProfile<DomainToViewModelMappingProfile>();
    cfg.AddProfile<ViewModelToDomainMappingProfile>();
});

// and then use it
var mapper = config.CreateMapper();
// or
var mapper = new Mapper(config);
var dest = mapper.Map<Source, Dest>(new Source());

在方法#2 中，您需要将映射器配置存储在某处(静态字段，DI)，然后在您的 Controller 中使用它。我想建议将 Mapper 实例注入(inject)到您的 Controller 中(例如，使用一些 DI 容器)。

希望对您有所帮助。