AutoMapper maps objects in the source child list to existing objects in the destination child collection

Question

I have the following situation:

public class Parent : EntityObject
{
    EntityCollection<Child> Children { get; set; }
}

public class Child : EntityObject
{
    int Id { get; set; }
    string Value1 { get; set; }
    string Value2 { get; set; }
}

public class ParentViewModel
{
    List<ChildViewModel> Children { get; set; }
}

public class ChildViewModel
{
    int Id { get; set; }
    string Value1 { get; set; }
    string Value2 { get; set; }
}

Mapper.CreateMap<ParentViewModel, Parent>();

Mapper.CreateMap<ChildViewModel, Child>();

Is it possible to get AutoMapper:

• Display objects in the list ParentViewModel.Childrenfor objects in Parent.ChildrenEntityCollection with the corresponding identifiers.
• Create new objects in Parent.Childrenfor objects in ParentViewModel.Children, where the object with the identifier from the source is not found in the mailing list.
• Remove objects from Parent.Childrenwhere the destination identifier does not exist in the source list.

Am I really doing all this wrong?

Answer 1

, automapper , . Map(). :

• , :

  foreach (var childviewmodel in parentviewmodel.Children)
  {
      if (!parent.Children.Select(c => c.Id).Contains(childviewmodel.Id))
      {
          parent.Children.Add(Mapper.Map<Child>(childviewmodel));
      }
  }
  

  ifs

• - IMappingAction BeforeMap:

  class PreventOverridingOnSameIds : IMappingAction<ParentViewModel, Parent>
  {
      public void Process (ParentViewModel source, Parent destination)
      {
          var matching_ids = source.Children.Select(c => c.Id).Intersect(destination.Children.Select(d => d.Id));
          foreach (var id in matching_ids)
          {
              source.Children = source.Children.Where(c => c.Id != id).ToList();
          }
      }
  }
  

  ..

  Mapper.CreateMap<ParentViewModel, Parent>()
      .BeforeMap<PreventOverridingOnSameIds>();
  

  .