Question

This is probably a simple answer, but i’m just starting to get the hand of AutoMapper.

Anyway, i have a domain object like this:

public class User
{
   public string Name { get; set; }
   public FacebookUser FacebookUser { get; set; }
}

And a ViewModel like this:

public class UserViewModel
{
   public string Name { get; set; }
   public long FacebookUniqueId { get; set; }
}

Here’s what i have in my AutoMapper configuration:

Mapper.CreateMap<User,UserViewModel>()
   .ForMember(dest => dest.FacebookUniqueId, opt => opt.MapFrom(src => src.FacebookUser.FacebookUniqueId))

But it throws an exception when the FacebookUser object is null, which is to be expected.

How do i tell AutoMapper:

Map UserViewModel.FacebookUniqueId to User.FacebookUser.FacebookUniqueId, except for when it’s null, then use 0.

Any ideas?

Answer 1

opt => opt.MapFrom(src => src.FacebookUser == null ? 0 : src.FacebookUser.FacebookUniqueId)

Yikes, if I had just checked if the first idea worked, thought the MapFrom method only took an expression that pointed to a property to resolve it that way…