Different mapping rules for same entity types in AutoMapper

Question

I have two entities: Order & OrderDTO And I'm using AutoMapper to map them together.

Based on some conditions I want these entities to be mapped differently.

In fact I want two or more different mapping rules (CreateMap) for these entities.

And When calling Map function I want to tell the engine which mapping rule to use.

Thanks to this question: Using the instance version of CreateMap and Map with a WCF service? one approach is using a different instance of mapper so each one can has it's own mapping rules:

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

Do you have any better solution?

As mentioned by Jimmy Bogard (Creator of AutoMapper) here: 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.

What lifecycle management is needed to be done?

Answer 1

I've ended up creating a new instance of mapper and caching them in a shared(static) concurrent dictionary.

here s my code (vb.net):

mapper factory:

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

different profiles for different scenarios:

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

and the mapper class:

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