Automapper map Generics types

Question

I have 2 class Data and MainData that I need to map

public class Data
{
    public Field<string> Results { get; set; }
    public Field<int> A { get; set; }
    public Field<int> B { get; set; }
}

public class Field<T>
{
 public string Label { get; set; }
 public T Value { get; set; }  
}

public class MainData{
 public string result {get; set; }
 public int a {get; set; }
 public int b {get; set; }
}

I've tried to map Data to MainData using automapper as follows:

Mapper.CreateMap(Data, MainData))
.ForMember(dest => dest.result, conf => conf.MapFrom(src => src.results.Value))
.ForMember(dest => dest.a, conf => conf.MapFrom(src => src.A.Value))
.ForMember(dest => dest.b, conf => conf.MapFrom(src => src.B.Value))

var destination = Mapper.Map<Data, MainData>(source);

It's never get mapped value to desination variable. All i get is new MainData object.