How to return Multiple Objects in LINQ - asp.net mvc 3

Question

I am stuck here with Linq query... I am just trying to get my hands on MVC via this very simple blog application.. I am hving these three entities

Post, AuthorDetails, CommentsDetails, //* in future will be adding categories, tags

i want to search using the searchterm passed into the methods, which will then search for that searchString in Post.Title, Post.Body,AuthorDetails.FirstName,AuthorDetails.LastName,CommentsDetails.Comments and waht to return something which i can cast to List<> ...please have a look what i have got so far.

Code..

 public List<Post> GetPostBySearchItem(string searchString)
        {
            List<Post> getAllPostsBySearchString = (from p in ePost.Posts
                                                    join a in ePost.AuthorDetails
                                                    on p.AuthorId equals a.Id
                                                    join c in ePost.CommentsDetails
                                                    on a.Id equals c.Id
                                                    where p.Title.Contains(searchString) || p.PostBody.Contains(searchString) || a.FirstName.Contains(searchString) || c.Comments.Contains(searchString)
                                                    select p).ToList();
            return getAllPostsBySearchString;

2 question here 1) whether the join statements are correct in this code 2) and how can i return something like this select P for Posts, A for AuthoreDetails and c for CommentsDetails...

Not an answer to your question directly, but it seems like you are trying to add search capability to your site... I would highly recommend looking at Lucene for .Net to add such functionality. You can find an example here ifdefined.com/blog/post/2009/02/… — labroo
– labroo, Commented Sep 7, 2011 at 22:10
Is there a reason you're using joins rather than associations here? If you establish associations from Post to Comments/Authors/Categories/etc, you could return List<Post> and navigate to the children in your view assuming you eager load the children appropriatly. Sounds like you're going through much of the same thing I did with www.ThinqLinq.com. You're free to check out my source in the file downloads at link. — Jim Wooley
– Jim Wooley, Commented Sep 8, 2011 at 15:25

jmogera · Accepted Answer · 2011-09-07 21:19:56Z

2

Your question #2: you simply have to return with "new" like this:

select new { Post = p, AuthorDetail = a, CommentDetail = c}).ToList()

instead of:

select p).ToList();

Look up Anonymous Type

answered Sep 7, 2011 at 21:19

jmogera

1,7593 gold badges31 silver badges65 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

patel.milanb Over a year ago

Thx... i have tried that and tried again ...its simply giving me the error " Error 1 Cannot implicitly convert type 'System.Collections.Generic.List<AnonymousType#1>' to 'System.Collections.Generic.List<MvcMBlog1.Models.Post>'

patel.milanb Over a year ago

the problem is here.. what should i do here .... List<Post> getAllPostsBySearchString .. i have also tried var.. just to let you know...

jmogera Over a year ago

Yes, because your return type is List<Post>. According your question was "how can I return something like..." that would be anonymous type, and you can't return a Post. The only other way you can do it is top have the AuthorDetail and CommentDetail within the Post object. Then your return type will work. Check the example: msdn.microsoft.com/en-us/library/bb425822.aspx

patel.milanb Over a year ago

thats great... works fine... just to confirm my LINQ joins are fine ?

Collectives™ on Stack Overflow

How to return Multiple Objects in LINQ - asp.net mvc 3

Code..

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

Code..

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related