AutoMapper Map single list on source object into two lists on destination object

Question

I'm attempting to use AutoMapper to map from a Domain-object that contains a list of objects, where I have a boolean property, that I want to use a the property that AutoMapper uses to split that list into two destinations on the destination object.

My basic domain looks like this (source)

//Domain object
public class Article
{
  public bool IsActive { get; set; }
}

so my source will be an IList<Article>

My view looks like this (destination)

//DTO
public class ViewAllArticles
{
  public IList<ViewArticle> ActiveArticles { get; set; }
  public ILIst<ViewArticle> InactiveArticles { get; set; }
}

public class ViewArticle
{
  public bool IsActive { get; set; }
}

Wanted mapping

//wanted mapping code (source to destination)
Mapper.Map<IList<Article>, ViewAllArticles>(collectionOfAllArticles)

where ActiveArticles contain only the articles with "IsActive=true", and vice-versa for InactiveArticles.

Hope one of you can help me get started doing this kind of mapping, that I would find hugely useful.

Thanks in advance.

score 5 · Accepted Answer · answered Jul 19 '12 at 14:44

You can do it this way

internal class StartNewDemo
{
    public static void Main(string[] args)
    {
        Mapper.CreateMap<IList<Article>, ViewAllArticles>()
            .ForMember(map => map.ActiveArticles, opt => opt.MapFrom(x => x.Where(y => y.IsActive)))
            .ForMember(map => map.InactiveArticles, opt => opt.MapFrom(x => x.Where(y => !y.IsActive)));

        var list = new List<Article>() { new Article { IsActive=true }, new Article { IsActive = false } };
        var result = Mapper.Map<List<Article>, ViewAllArticles>( list );
    }
}

score 1 · Answer 2 · answered Jul 19 '12 at 14:28

Mapper.CreateMap<IList<Article>, ViewAllArticles>()
  .AfterMap( (arts , artsvm) => 
{
   //var artsvm = new ViewAllArticles();
   artsvm.ActiveArticles = arts.Where(a=> IsActive==true).ToList();
   artsvm.InactiveArticles = arts.Where(a=> IsActive==false).ToList();
}

You could also do ConvertUsing, and the only difference is you would start out with a new ViewAllArticles because you will be responsible for creating it. The only reason I didn't do that here, is because I couldn't remember if ConvertUsing allows a multiline lambda, but I would actually try ConvertUsing instead and see if that works.

AutoMapper Map single list on source object into two lists on destination object

2 Answers2

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