Question

I have an N-N relationship between two elements Sfera and Contenuti.

On the Sfera item I see the Contenuti entity set and in the Contenuti I see the Sfera set..

When I add a new item by code i use a structure like:

using (IndexDB DB = new IndexDB())
        {
            try
            {
                var newContenuto = new Contenuto();
                newContenuto.Cancellato = false;
                newContenuto.PK_Content_ID = tt_content_id;
                newContenuto.URL = URL;
                foreach(long sphere in SphereID)
                {
                    try
                    {
                        var sfere = from sfera in DB.Sfera where sfera.PK_Sfera == sphere select sfera;
                        newContenuto.Sfera.Add(sfere.First());
                        sfere.First().Contenuto.Add(newContenuto);
                    }
                    catch (Exception exc)
                    {
                        return new StandardResponse() {Success = false, Message = exc.Message};
                    }
                }
                DB.AddToContenuto(newContenuto);
                DB.SaveChanges();
                return new StandardResponse() {Success = true};
            }
            catch (Exception e)
            {
                return new StandardResponse() { Success = false, Message = e.Message + e.StackTrace };
            }

If I take a look on my DB, it stores well my relation between the two elements in the right “N-N” table…. But when i try to access the elements Contenuto.Sfera and Sfera.Contenuto are ALWAYS empty set…

To access I do something like that:

using (IndexDB DB = new IndexDB())
        {
            var sfere = from sfera in DB.Sfera where sfera.PK_Sfera == IDSfera && sfera.Attiva select sfera;

            if (!sfere.Any())
            {
                response.Add(new UrlResponse() { Success = false, ErrorMessage = "" });
            }
            var sferaSelezionata = sfere.First();
//HERE sferaSelezionata.Contenuto.Count == 0 even if on DB there are MANY "connections"
}

}

How can I handle this?

Thank you very much!

Answer 1

Try using Include() in your query.

var sfere = from sfera in DB.Sfera.Include("Contenuto") where sfera.PK_Sfera == IDSfera && sfera.Attiva select sfera;