I have the following model:
public class Tag
{
public int Id { get; set; }
public string Name { get; set; }
}
I want to be able to
This is because you are trying to map to the actual destination type rather than a property of the destination type. You can achieve what you want with:
Mapper.CreateMap().ConvertUsing(source => source.Name ?? string.Empty);
although it would be a lot simpler just to override ToString on the Tag class.