AutoMapper-使用构造函数映射子集合

Question

I have the following classes, and I need to map the collection of posts in the Thread class to a paginated collection of posts in the ThreadView class, but I'm completely stumped on how to go about it.

// Database class
public class Thread
{
    public virtual int Id { get; set; }
    public virtual string Title { get; set; }
    public virtual IEnumerable<Post> Posts { get; set;}
}

// View class
public class ThreadView
{
    public int Id { get; set; }
    public string Title { get; set; }
    public PaginatedList<PostView> Posts { get; set; }
}

public class PaginatedList<T> : List<T>
{
    public PaginatedList<IEnumerable<T> source, int page)
    {
        ...
    }
}

My mappings are simply:

Mapper.CreateMap<Thread, ThreadView>();
Mapper.CreateMap<Post, PostView>();

And my action method looks like this:

public ViewResult ViewThread(int threadId, int page = 1)
{
    var thread = _forumService.GetThread(threadId, page);
    var viewModel = Mapper.Map<Thread, ThreadView>(thread);

    return View(viewModel);
} 

But this obviously doesn't work. Can anyone help?

Thanks

Update

I think I'm gonna settle for doing it like this for now, even though it smells a bit:

public ViewResult ViewThread(int id, int page = 1)
{
    var thread = _forumService.GetThread(id, page);
    var posts = Mapper.Map<IEnumerable<Post>, IEnumerable<PostView>>(thread.Posts);

    var viewModel = new ThreadView {
        Id = thread.Id,
        Title = thread.Title,
        Posts = new PaginatedList<PostView>(posts, page)
    };

    return View(viewModel);
}

Unless anyone else knows how this can be done?

Answer 1

As it appears you are returning all the Post items anyway, you could modify the action to created the PaginatedList from your Thread object instead of ThreadView. Something like:

public ViewResult ViewThread(int threadId, int page = 1)
{
    var thread = _forumService.GetThread(threadId, page);
    thread.Posts = new PaginatedList(thread.Post, page);
    var viewModel = Mapper.Map<Thread, ThreadView>(thread);

    return View(viewModel);
} 

There's probably not an easy way to do just using AutoMapper.

EDIT: Oh, just noticed the page is being passed into your service. So this answer probably isn't at all what you want. Let me know and I'll delete it if that's the case.