AutoMapper: “Ignore the rest”?

Question

Is there a way to tell AutoMapper to ignore all of the properties except the ones which are mapped explicitly?

I have external DTO classes which are likely to change from the outside and I want to avoid specifying each property to be ignored explicitly, since adding new properties will break the functionality (cause exceptions) when trying to map them into my own objects.

Answer 1

In version of 3.3.1 you simply can use IgnoreAllPropertiesWithAnInaccessibleSetter() or IgnoreAllSourcePropertiesWithAnInaccessibleSetter() methods.

Answer 2

I've been able to do this the following way:

Mapper.CreateMap<SourceType, DestinationType>().ForAllMembers(opt => opt.Ignore());
Mapper.CreateMap<SourceType, DestinationType>().ForMember(/*Do explicit mapping 1 here*/);
Mapper.CreateMap<SourceType, DestinationType>().ForMember(/*Do explicit mapping 2 here*/);
...

Note: I'm using AutoMapper v.2.0.

Answer 3

I know this is an old question, but @jmoerdyk in your question:

How would you use this in a chained CreateMap() expression in a Profile?

you can use this answer like this inside the Profile ctor

this.IgnoreUnmapped();
CreateMap<TSource, Tdestination>(MemberList.Destination)
.ForMember(dest => dest.SomeProp, opt => opt.MapFrom(src => src.OtherProp));

Answer 4

There's been a few years since the question has been asked, but this extension method seems cleaner to me, using current version of AutoMapper (3.2.1):

public static IMappingExpression<TSource, TDestination> IgnoreUnmappedProperties<TSource, TDestination>(this IMappingExpression<TSource, TDestination> expression)
{
    var typeMap = Mapper.FindTypeMapFor<TSource, TDestination>();
    if (typeMap != null)
    {
        foreach (var unmappedPropertyName in typeMap.GetUnmappedPropertyNames())
        {
            expression.ForMember(unmappedPropertyName, opt => opt.Ignore());
        }
    }

    return expression;
}