AutoMapper - skip whole object from child collection

Question

I have a parent class that has a list of children objects. Child has a bool property that defines if it should be in the Parent list after mapping. Parent has the same property but it's not the one that's relevant in this case:

class Parent
{
   public List<Child> Children { get; set; }
   public bool WillMap { get; set; }
   // more stuff
}
class Child
{
   public bool WillMap { get; set; }
   // more things
}

I was wondering if a mapping can be written that will end up with a Parent with a collection of Child objects that have WillMap == true? I know about conditional mapping and that we can do something like

CreateMap<Parent, Parent>()
   .ForMember(d => d.Children, opt => opt.Condition(s => s.WillMap == true));

but in this case it's the Parent's WillMap property that's being targeted.

Thanks.

Answer 1

.ForMember(dest => dest.Children, opt => opt.MapFrom(source => source.Children.Where(child => child.WillMap));

Answer 2

You can perform filtering inside MapFrom

.ForMember(d => d.Children, opt => opt.MapFrom((s, d, obje, conext) => s.WillMap && s.Children != null ? conext.Mapper.Map<Child>(s.Children.Where(x => x.WillMap).ToList()) : null));

Or create a custom converter with filtering inside:

    public class ParentConverter : ITypeConverter<Parent, Parent>
    {
        public Parent Convert(ResolutionContext context)
        {
              // implement conversion logic  


        }
    }

http://docs.automapper.org/en/stable/Custom-type-converters.html