Question

使用AutoMapper.Extensions.Expression的表达式映射未映射表达式。

这是我的模特：

public class UserDto
{
    public int Id { get; set; }
    public User User { get; set; }
    //other info
}

public class User
{
    public string Email { get; set; }
    //other info
}


public class UserEntity
{
    public int Id { get; set; }
    public string Email { get; set; }
    //other info
}

我的映射器：

public static class MapperConfiguration
{
    public static void Configure()
    {
        Mapper.Initialize(cfg =>
        {
            cfg.AddProfile(new UserDtoProfile());
        });
    }
}

internal class UserDtoProfile : Profile
{
    public UserDtoProfile()
    {
        CreateMap<UserDto, UserEntity>()
            .ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.Id))
            .ForMember(dest => dest.Email, opt => opt.MapFrom(src => src.User.Email));

        CreateMap<UserEntity, UserDto>()
            .ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.Id))
            .ForMember(dest => dest.User, opt => opt.MapFrom(src => Mapper.Map<UserEntity>(src)));

        CreateMap<UserEntity, User>()
           .ForMember(dest => dest.Email, opt => opt.MapFrom(src => src.Email)).ReverseMap();
    }
}

添加摘要以重现该问题：

static void Main(string[] args)
{
    MapperConfiguration.Configure();
    var email = "test@test.com";
    Expression<Func<UserDto, bool>> filterExpression = x => x.User.Email == email;
    var expression = Mapper.Map<Expression<Func<UserEntity, bool>>>(filterExpression);
    Console.WriteLine("Old Expression : " + filterExpression.Body);
    Console.WriteLine("New Expression : " + expression.Body);
    Console.Read();
}

此输出为：

旧表达式：（x.User.Email ==“ asd”）
新表达式：（x.User.Email ==“ asd”）

但是，我希望它能输出：

旧表达式：（x.User.Email ==“ asd”）
新表达式：（x.Email ==“ asd”）

无法正常运行的特定行是：

Expression<Func<UserDto, bool>> filterExpression = x => x.User.Email == email;
var expression = Mapper.Map<Expression<Func<UserEntity, bool>>>(filterExpression);

我正在使用AutoMapper v8.0.0和AutoMapper.Extensions.Expression v2.0.0

Answer 1

您忘记配置表达式映射。您的设置应为：

Mapper.Initialize(cfg =>
{
    cfg.AddExpressionMapping();
    cfg.AddProfile(new UserDtoProfile());
});

我还没有真正使用过AutoMapper，也从未使用过表达式映射，但是根据this github issue，对于表达式来说，映射似乎是向后的。您当前的映射将不起作用，并且在执行时会崩溃。您需要将映射更改为：

internal class UserDtoProfile : Profile
{
    public UserDtoProfile()
    {
        CreateMap<UserDto, UserEntity>()
            .ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.Id))
            .ForMember(dest => dest.Email, opt => opt.MapFrom(src => src.User.Email))
            .ReverseMap();

        CreateMap<UserEntity, User>()
           .ForMember(dest => dest.Email, opt => opt.MapFrom(src => src.Email)).ReverseMap();
    }
}

运行此命令可获得输出：

旧表达式：（x.User.Email ==“ asd”）
新表达式：（x.Email ==“ asd”）

自动映射器表达式映射问题

1 个答案: