DbContext set<> include dont work - entity-framework

Question

//Site entity
public class Site
{
public long Id { get; set; }
public string Title { get; set; }
public virtual List<Language> Languages { get; set; }
}
//language entity
public class Language
{
public long Id { get; set; }
public string Title { get; set; }
public string ShortName { get; set; }
public virtual List<Site> Sites { get; set; }
}
//my context with custom connection and transaction
public class PortalBaseContext : DbContext
{
public PortalBaseContext(DbConnection conn)
: base(conn, false)
{
Database.UseTransaction((DbTransaction)PersistContext.Transaction);
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Site>().ToTable("TblSite");
modelBuilder.Entity<Language>().ToTable("TblLanguage");
modelBuilder.Entity<Site>().
HasMany(c => c.Languages).
WithMany(p => p.Sites).
Map(
m =>
{
m.MapLeftKey("LanguageId");
m.MapRightKey("SiteId");
m.ToTable("TblSiteLanguage");
});
}
public DbSet<Site> TblSite { get; set; }
public DbSet<Language> TblLanguage { get; set; }
}
PortalBaseContext c = new PortalBaseContext( );
//Part1
DbSet<Site> query = c.Set<Site>();
query.Include("Languages");
lst = query.ToList();
//Part2
//lst = c.TblSite.Include("Languages").ToList();
in part1 include not work!!
if comment part1 and use part2 include work correctly!!
i use custom connection and transaction per request and want load
sub property for each class.
in part1 include not work!!
if comment part1 and use part2 include work correctly!!
i use custom connection and transaction per request and want load
sub property for each class.

Answer 1

Include is a non destructive method. It returns a new enumerable where each item will have the specified related entities loaded when materialized; the original DBSet you're invoking it on isn't modified in any way.
You need to apply ToList to the value returned by Include. Change this:
DbSet<Site> query = c.Set<Site>();
query.Include("Languages");
lst = query.ToList();
to this:
DbSet<Site> query = c.Set<Site>();
lst = query.Include("Languages").ToList();