使用Automapper映射嵌套集合

public class SourceItem
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class Source
{
    public List<SourceItem> Items { get; set; }
}

public class DestinationItem
{
    public int Identifier { get; set; }
    public string DisplayName { get; set; }
}

public class Destination
{
    public List<DestinationItem> Elements { get; set; }
}

var config = new MapperConfiguration(cfg =>
{
    cfg.CreateMap<SourceItem, DestinationItem>()
        .ForMember(dest => dest.Identifier, opt => opt.MapFrom(src => src.Id))
        .ForMember(dest => dest.DisplayName, opt => opt.MapFrom(src => src.Name));
    
    cfg.CreateMap<Source, Destination>()
        .ForMember(dest => dest.Elements, opt => opt.MapFrom(src => src.Items));
});

var mapper = config.CreateMapper();

var source = new Source
{
    Items = new List<SourceItem>
    {
        new SourceItem { Id = 1, Name = "Item1" },
        new SourceItem { Id = 2, Name = "Item2" }
    }
};

var destination = mapper.Map<Destination>(source);

cfg.CreateMap<Source, Destination>()
    .ForMember(dest => dest.Elements, opt => opt.MapFrom(src => src.Items ?? new List<SourceItem>()));