UseDestinationValue only when destination property is not null

Question

How to configure AutoMapper mapping when I want to use behaviour from UseDestinationValue method, but only when destination property is NOT null.

Answer 1

Had this same problem, but with EF. Cryss' comment about using BeforeMap pointed me in the right direction.

I ended up with code similar to:

In the Configure() method:

Mapper.CreateMap()
           .AfterMap((s, d) => { MapDetailsAction(s, d); })
           .ForMember(dest => dest.Details, opt => opt.UseDestinationValue());

Then the Action:

Action MapDetailsAction = (source, destination) =>
        {
            if (destination.Details == null)
            {
                destination.Details = new Details();
                destination.Details =
                    Mapper.Map(
                    source.Details, destination.Details);
            }
        };