LINQ to XML gets no data with schema set

<CarsForSale xmlns="http://schemas.sharplogic.net/CarSales.xsd">
  <CarForSale>

XElement doc = XElement.Load(HttpContext.Current.Server.MapPath("App_Data/XML/CarsForSale.xml"));

var cars2 = from d in doc.Descendants("CarForSale")
            select d;

var ns    = "http://schemas.sharplogic.net/CarSales.xsd";
var cars2 = from d in doc.Descendants(ns + "CarForSale")
            select d;

var cars2 = from d in doc.Descendants()
            where d.Name.LocalName == "CarForSale"
            select d;

XNamespace ns = doc.Root.Name.Namespace;