AutoMapper: Map Source property of concrete subclass to an EnumValue in Destination class

Question

I would like to define a mapping (or even a TypeConverter/Resolver) for the following classes: Destination:

   public class Destination
    {
        public DestinationEnum EnumProperty { get; set; }

        public Destination()
        {
            EnumProperty = DestinationEnum.undefined;
        }
    }

    public enum DestinationEnum
    {
        oneValue,
        anotherValue, 
        undefined
    }

Source:

    public enum SourceEnum
    { 
        fu,
        ba
    }

    public enum AnotherSourceEnum
    { 
        first,
        second, 
        third
    }

    public class Source
    {
        public SourceEnum SourceEnumVal { get; set; }
    }

    public class ConcreteSource : Source
    {
        public AnotherSourceEnum ConcreteSourceEnumVal { get; set; }
    }

What would the AutoMapper Mapping look like, if I want to specify a destination value of the DestinationEnum in the Destination class depending on the concrete Source Type? E.g.

• if the mapper maps from class "Source" to "Destination", the Destination.EnumProperty should be set to "undefined" if Source.SourceEnumVal == fu
• if the mapper maps from class "source" to "Destination", the Destination.EnumProperty should be set to "oneValue" if Source.SourceEnumVal == "ba"
• if the mapper maps from class "ConcreteSource" to "Destination", the Destination.EnumProperty should be set to "oneValue" if ConcreteSource.ConcreteSourceEnumVal == "second"
• if the the mapper maps from class "ConcreteSource" to "Destination", the Destination.EnumProperty should be set to "undefined" if ConcreteSource.ConcreteSourceEnumVal != "second"

Answer 1

You would create two maps:

Mapper.CreateMap<Source, Destination>();
Mapper.CreateMap<ConcreteSource, Destination>();

Then do a custom resolver for each map:

Mapper.CreateMap<Source, Destination>()
    .ForMember(dest => dest.EnumProperty, opt => opt.ResolveUsing<FirstResolver>());

Your second ConcreteSource map would use a different resolver:

Mapper.CreateMap<ConcreteSource, Destination>()
    .ForMember(dest => dest.EnumProperty, opt => opt.ResolveUsing<SecondResolver>());

AutoMapper chooses the mapping to use based on both the source and destination type, so the correct resolver will be chosen no matter which of the source types you use.