Mapping one source class to multiple derived classes with automapper

Question

Suppose i have a source class:

public class Source {     //Several properties that can be mapped to DerivedBase and its subclasses } 

And some destination classes:

public class DestinationBase {      //Several properties }  public class DestinationDerived1 : DestinationBase {      //Several properties }  public class DestinationDerived2 : DestinationBase {      //Several properties } 

Then I wish the derived destination classes to inherit the automapper configuration of the baseclass because I do not want to have to repeat it, is there any way to achieve this?

Mapper.CreateMap<Source, DestinationBase>()     .ForMember(...)     // Many more specific configurations that should not have to be repeated for the derived classes     .ForMember(...);  Mapper.CreateMap<Source, DestinationDerived1 >()     .ForMember(...); Mapper.CreateMap<Source, DestinationDerived2 >()     .ForMember(...); 

When I write it like this it does not use the base mappings at all, and include doesn't seem to help me.

Edit: This is what I get:

public class Source {     public string Test { get; set; }     public string Test2 { get; set; } }  public class DestinationBase {     public string Test3 { get; set; } }  public class DestinationDerived1 : DestinationBase {     public string Test4 { get; set; } }  public class DestinationDerived2 : DestinationBase {     public string Test5 { get; set; } } 

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Mapper.CreateMap<Source, DestinationBase>()               .ForMember(d => d.Test3, e => e.MapFrom(s => s.Test))               .Include<Source, DestinationDerived1>()               .Include<Source, DestinationDerived2>();          Mapper.CreateMap<Source, DestinationDerived1>()               .ForMember(d => d.Test4, e => e.MapFrom(s => s.Test2));          Mapper.CreateMap<Source, DestinationDerived2>()               .ForMember(d => d.Test5, e => e.MapFrom(s => s.Test2)); 

AutoMapper.AutoMapperConfigurationException : Unmapped members were found. Review the types and members below.

Add a custom mapping expression, ignore, add a custom resolver, or modify the source/destination type

Source -> DestinationDerived1 (Destination member list)

Test3

Answer 1

Include derived mappings into base mapping:

Mapper.CreateMap<Source, DestinationBase>()     .ForMember(d => d.Id, op => op.MapFrom(s => s.Id)) // you can remove this     .Include<Source, DestinationDerived1>()     .Include<Source, DestinationDerived2>();  Mapper.CreateMap<Source, DestinationDerived1>()     .ForMember(d => d.Name, op => op.MapFrom(s => s.Text))     .ForMember(d => d.Value2, op => op.MapFrom(s => s.Amount));  Mapper.CreateMap<Source, DestinationDerived2>()     .ForMember(d => d.Value, op => op.MapFrom(s => s.Amount)); 

Usage:

Mapper.AssertConfigurationIsValid(); var s = new Source() { Id = 2, Amount = 10M, Text = "foo" }; var d1 = Mapper.Map<DestinationDerived1>(s); var d2 = Mapper.Map<DestinationDerived2>(s); 

See Mapping inheritance on AutoMapper wiki.

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UPDATE: Here is full code of classes which works as it should.

public class Source {     public int Id { get; set; }     public string Text { get; set; }     public decimal Amount { get; set; } }  public class DestinationBase {     public int Id { get; set; } }  public class DestinationDerived1 : DestinationBase {     public string Name { get; set; }     public decimal Value2 { get; set; } }  public class DestinationDerived2 : DestinationBase {     public decimal Value { get; set; } } 

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UPDATE (workaround of AutoMapper bug):

public static class Extensions {     public static IMappingExpression<Source, TDestination> MapBase<TDestination>(         this IMappingExpression<Source, TDestination> mapping)         where TDestination: DestinationBase     {         // all base class mappings goes here         return mapping.ForMember(d => d.Test3, e => e.MapFrom(s => s.Test));     } } 

And all mappings:

    Mapper.CreateMap<Source, DestinationBase>()           .Include<Source, DestinationDerived1>()           .Include<Source, DestinationDerived2>()           .MapBase();      Mapper.CreateMap<Source, DestinationDerived1>()           .MapBase()           .ForMember(d => d.Test4, e => e.MapFrom(s => s.Test2));      Mapper.CreateMap<Source, DestinationDerived2>()           .MapBase()           .ForMember(d => d.Test5, e => e.MapFrom(s => s.Test2)); 

Answer 2

For Automapper 8.0.
Current version has new method IncludeAllDerived
Here's working example:

        var config = new MapperConfiguration(cfg =>         {             cfg.CreateMap<Source, DestinationBase>()                 .ForMember(dest => dest.Test3, opt => opt.MapFrom(src => src.Test))                 .IncludeAllDerived();              cfg.CreateMap<Source, DestinationDerived1>()                 .ForMember(dest => dest.Test4, opt => opt.MapFrom(src => src.Test2));              cfg.CreateMap<Source, DestinationDerived2>()                   .ForMember(dest => dest.Test5, opt => opt.MapFrom(src => src.Test2));         });          var mapper = config.CreateMapper();          var source = new Source { Test = "SourceTestProperty", Test2 = "SourceTest2Property" };         var d1 = mapper.Map<DestinationDerived1>(source);         var d2 = mapper.Map<DestinationDerived2>(source);          Assert.Equal("SourceTestProperty", d1.Test3);         Assert.Equal("SourceTest2Property", d1.Test4);          Assert.Equal("SourceTestProperty", d2.Test3);         Assert.Equal("SourceTest2Property", d2.Test5);