Automapper map custom collections - automapper

Question

Hello. I have a list that looks like this one:
public class PagedList<T> : List<T>
{
public PagedList(IEnumerable<T> collection) : base(collection)
{ }
public int TotalItems { get; set; }
public int CurrentPage { get; set; }
public int PageSize { get; set; }
//some other properties
}
and used in repository for paging
public PagedList<TEntity> GetPaged(int page)
{
var pagedEntities = some_query;
return pagedEntities.AsPagedList(totalResults, page, pageSize);
}
The same PagedList is also used in asp mvc view models for paging.
Is it possible to map this collections using Automapper with all the properties TotalItems/CurrentPage/... ?
PagedList<DbItem> dbItems = _repository.GetPages(page);
var viewItems = new PagedList<SomeItemView>();
Mapper.Map(dbItems , viewItems);
Tahnk You !

Answer 1

This worked for me. Are you looking for something more generic?
public class DbItem
{
public int Id { get; set; }
public string Name { get; set; }
}
public class ViewItem
{
public int Id { get; set; }
public string Name { get; set; }
}
public class PagedList<T>: List<T>
{
public int TotalItems { get; set; }
public int CurrentPage { get; set; }
public int PageSize { get; set; }
}
class Program
{
static void Main(string[] args)
{
MapItems();
}
public static void MapItems()
{
Mapper.CreateMap<DbItem, ViewItem>();
Mapper.CreateMap<PagedList<DbItem>, PagedList<ViewItem>>()
.AfterMap((s, d) => Mapper.Map<List<DbItem>, List<ViewItem>>(s, d));
var dbList = new PagedList<DbItem>
{
new DbItem {Id = 1, Name = "a"},
new DbItem {Id = 2, Name = "b"}
};
dbList.TotalItems = 2;
dbList.CurrentPage = 1;
dbList.PageSize = 10;
var viewList = Mapper.Map<PagedList<DbItem>, PagedList<ViewItem>>(dbList);
Console.WriteLine(viewList.TotalItems);
Console.WriteLine(viewList.CurrentPage);
Console.WriteLine(viewList.PageSize);
Console.WriteLine(viewList[0].Id + " " + viewList[0].Name);
Console.WriteLine(viewList[1].Id + " " + viewList[1].Name);
Console.ReadLine();
}
}

Answer 2

What you need is a custom type converter
public class PagedListConverter<TIn, TOut> : ITypeConverter<IPagedList<TIn>, IPagedList<TOut>>
{
public IPagedList<TOut> Convert(AutoMapper.ResolutionContext context)
{
var source = (IPagedList<TIn>)context.SourceValue;
var mapped = Mapper.Map<IList<TOut>>(source);
return new StaticPagedList<TOut>(mapped, source.GetMetaData());
}
}
Usage:
Mapper.CreateMap<IPagedList<Company>, IPagedList<CompanyViewModel>>().ConvertUsing<PagedListConverter<Company, CompanyViewModel>>();

Answer 3

For those who have faced the similar problem recently, and as an update to NoPyGod's answer, you can achieve the general mapping using ITypeConverter. According to the official documentation:
AutoMapper also supports open generic type converters with any number of generic arguments:
var configuration = new MapperConfiguration(cfg =>
cfg.CreateMap(typeof(Source<>), typeof(Destination<>)).ConvertUsing(typeof(Converter<,>)));
The closed type from Source will be the first generic argument, and the closed type of Destination will be the second argument to close Converter<,>.
So the custom type converter would be:
private class Converter<TSource, TDestination>
: ITypeConverter<PagedList<TSource>, PagedList<TDestination>>
{
public PagedList<TDestination> Convert(
PagedList<TSource> source,
PagedList<TDestination> destination,
ResolutionContext context) =>
new PagedList<TDestination>(
context.Mapper.Map<List<TSource>, List<TDestination>>(source));
/* Additional settings comes here. */
}
And then register it:
this.CreateMap(typeof(PagedList<>), typeof(PagedList<>)).ConvertUsing(typeof(Converter<,>));