In my Custom ObjectContext class I have my entity collections exposed as IObjectSet so they can be unit-tested. I have run into a problem when I use this ObjectContext in a compiled query and call the "Include" extension method (From Julie Lerman's blog http://thedatafarm.com/blog/data-access/agile-entity-framework-4-repository-part-5-iobjectset/) and in her book Programming Entity Framework 2nd edition on pages 722-723. Here is the code:
Query:
public class CommunityPostsBySlugQuery : QueryBase<IEnumerable<CommunityPost>>
{
private static readonly Expression<Func<Database, string, IEnumerable<CommunityPost>>> expression = (database, slug) => database.CommunityPosts.Include("Comments").Where(x => x.Site.Slug == slug).OrderByDescending(x => x.DatePosted);
private static readonly Func<Database, string, IEnumerable<CommunityPost>> plainQuery = expression.Compile();
private static readonly Func<Database, string, IEnumerable<CommunityPost>> compiledQuery = CompiledQuery.Compile(expression);
private readonly string _slug;
public CommunityPostsBySlugQuery(bool useCompiled, string slug): base(useCompiled)
{
_slug = slug;
}
public override IEnumerable<CommunityPost> Execute(Database database)
{
return base.UseCompiled ? compiledQuery(database, _slug) : plainQuery(database, _slug);
}
}
Extension
public static class ObjectQueryExtension
{
public static IQueryable<T> Include<T>(this IQueryable<T> source, string path)
{
var objectQuery = source as ObjectQuery<T>;
return objectQuery == null ? source : objectQuery.Include(path);
}
}
LINQ to Entities does not recognize the method 'System.Linq.IQueryable1[MyPocoObject] Include[MyIncludedPocoObject](System.Linq.IQueryable1[MyPocoObject], System.String)' method, and this method cannot be translated into a store expression.
If I use this same query on ObjectSet collections rather than IObjectSet it works fine. If I simply run this query without precompiling it works fine. What am I missing here?
