Question

I know many:many isn’t supported in Linq2Sql but I am working on a workaround

I am working with my little SO clone and I have a table with Questions and a table with Tags and a linking table QuestionTag so I have a classic many:many relationship between Questions and Tags.

To display the list of Questions on the front page I have this class I want to fill up from a Linq2Sql query

public class ListQuestion {    public int QuestionID { get; set; }    public string Title{ get; set; }    public IEnumerable<Tag> Tags { get; set; } }   public IEnumerable<ListQuestion> GetQuestions() {    from q in Questions    .................    select new ListQuestion{ ... } } 

The problem is how should I fill up the Tag collection. I found out this isn’t possible to do in 1 single query so I have divided this into 2 queries, 1 to get the questions and 1 to get the tags and later try to join them. I know many:many is supported in Entity framework so how do they do it? How would you do this? Any alternative approach? The query should of course be efficient.

Answer 1

This may work for your case;

from q in Questions select new ListQuestion  {    Tags = q.QuestionTags.Select(qt => qt.Tag),   QuestionId = q.ID,   Title = q.Title }