Question

I have a linq query where I’m trying to return all MlaArticles that are related to all other WebObjects but I’m getting the error: The specified type member 'RelatedWebObjectIds' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported.

Here’s the Model…

public abstract class WebObject : IValidatableObject
{
    public WebObject()
    {
        this.Id = Guid.NewGuid();
        RelatedTags = new List<Tag>();
        RelatedWebObjects = new List<WebObject>();
    }

    [Key, DatabaseGenerated(DatabaseGeneratedOption.None)]
    public Guid Id { get; set; }
    public virtual ICollection<WebObject> RelatedWebObjects { get; set; }
    public IList<Guid> RelatedWebObjectIds { get; set; }
}

Thanks for your help…

List<MlaArticle> assignedWebObjects = (from e in db.MlaArticles
                                       where
                                           (from w in db.WebObjects
                                            from r in w.RelatedWebObjectIds
                                            where w.Id == id
                                            select r).Contains(e.Id)
                                       select e).OrderBy(x => x.Title).ToList();

New query. Produces different error: WebObject does not contain a definition for 'Contains' and the best extension method overload ... has some invalid arguments.

List<MlaArticle> assignedWebObjects = (from e in db.MlaArticles
                                       where
                                           (from w in db.WebObjects
                                            from r in w.RelatedWebObjects
                                            where w.Id == id
                                            select r.RelatedWebObjectIds).Contains(e.Id)
                                       select e).OrderBy(x => x.Title).ToList();

Answer 1

Is there a RelatedWebObjects navigation property in your MlaArticle entity? If there is, you can do that instead:

List<MlaArticle> assignedWebObjects = (from e in db.MlaArticles
                                       where
                                           (from w in db.WebObjects
                                            from r in w.RelatedWebObjects
                                            where w.Id == id
                                            select r.Id).Contains(e.Id)
                                       select e).OrderBy(x => x.Title).ToList();