c# - AutoMapper 中相同实体类型的不同映射规则

Question

我有两个实体:Order 和 OrderDTO 我正在使用 AutoMapper 将它们映射在一起。

基于某些条件，我希望这些实体以不同方式映射。

事实上，我需要为这些实体使用两个或多个不同的映射规则 (CreateMap)。

并且在调用 Map 函数时，我想告诉引擎要使用哪个映射规则。

感谢这个问题:Using the instance version of CreateMap and Map with a WCF service?一种方法是使用不同的映射器实例，这样每个实例都可以拥有自己的映射规则:

var configuration = new ConfigurationStore(new TypeMapFactory(), MapperRegistry.AllMappers());
var mapper = new MappingEngine(configuration);
configuration.CreateMap<Dto.Ticket, Entities.Ticket>()

你有更好的解决方案吗？

如 Jimmy Bogard(AutoMapper 的创建者) 所述:Using Profiles in Automapper to map the same types with different logic :

You're better off creating separate Configuration objects, and creating a separate MappingEngine for each. The Mapper class is merely a static facade over each of those, with some lifecycle management.

需要做哪些生命周期管理？

Answer 1

我最终创建了一个映射器的新实例并将它们缓存在共享(静态)并发字典中。

这是我的代码(vb.net):

映射器工厂:

Public Function CreateMapper() As IMapper Implements IMapperFactory.CreateMapper
            Dim nestedConfig = New ConfigurationStore(New TypeMapFactory, MapperRegistry.Mappers)
            Dim nestedMapper = New MappingEngine(nestedConfig)
            Return New AutomapperMapper(nestedConfig, nestedMapper)
 End Function

不同场景的不同配置文件:

Private Shared _mapperInstances As New Concurrent.ConcurrentDictionary(Of String, IMapper)

Public Shared ReadOnly Property Profile(profileName As String) As IMapper
            Get
                Return _mapperInstances.GetOrAdd(profileName, Function() _mapperFactory.CreateMapper)
            End Get
End Property

和映射器类:

Friend Class AutomapperMapper
        Implements IMapper

        Private _configuration As ConfigurationStore
        Private _mapper As MappingEngine

        Public Sub New()
            _configuration = AutoMapper.Mapper.Configuration
            _mapper = AutoMapper.Mapper.Engine
        End Sub

        Public Sub New(configuration As ConfigurationStore, mapper As MappingEngine)
            _configuration = configuration
            _mapper = mapper
        End Sub

        Public Sub CreateMap(Of TSource, TDestination)() Implements IMapper.CreateMap
            _configuration.CreateMap(Of TSource, TDestination)()
        End Sub

        Public Function Map(Of TSource, TDestination)(source As TSource, destination As TDestination) As TDestination Implements IMapper.Map
            Return _mapper.Map(Of TSource, TDestination)(source, destination)
        End Function

        Public Function Map(Of TSource, TDestination)(source As TSource) As TDestination Implements IMapper.Map
            Return _mapper.Map(Of TSource, TDestination)(source)
        End Function


    End Class