LINQ multi-table query: error on INCLUDE

Query: Given a cuisineID (type of cuisine), return the list of restaurants that offer that cuisine and also return the city for each og those restauarants (1 per restaurant). The RESTAURANT and CITY tables have a foreign-key relationship based on CITY_ID. I have added a Linq to SQL .dbml file (FVRG.dbml) and loaded all the tables for my database in the FVRGdatacontext file. When I look at the file, I can see the foreign key relationships between each of the tables. However, Intellisense does not recognize usage of the include statement and returns the following error. Can you please help? Regards, Susan

Error 1: 'System.Data.Linq.Table' does not contain a definition for 'Include' and no extension method 'Include' accepting a first argument of type 'System.Data.Linq.Table' could be found (are you missing a using directive or an assembly reference?) H:\ASP.Net\FVRG\DL\DLgetRestaurants.cs 20 68 DL

using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Configuration;
using System.Data.SqlClient;

namespace DL
{
    public class DLgetRestaurants
    {
        DL.FVRGDataContext db = new FVRGDataContext();

 开发者_JS百科       public IEnumerable <RESTAURANT> getRestaurants(string cuisineName)
        {

        var cuisineID = db.CUISINEs.First(s => s.CUISINE_NAME == cuisineName).CUISINE_ID;


            var restaurantList = from RESTAURANT in db.RESTAURANTs.Include("CITies")
                                 where RESTAURANT.CITY.Any(t => t.CITY_ID == 2)
                                 select RESTAURANT;

            return restaurantList;
        }
    }
}

---

var db = new YourDataContext();

List<Restaurant> result = (from c in db.Cities
                           join r in db.Restaurants on c.CityID equals r.CityID
                           where c.CuisineName == cuisineName && c.CityID == cityID
                           select r).ToList(); 

return result;

That is, of course, as long as you have a database table called Cities and a table called Restaurants with a CityID foreign key to the primary key of the Cities table.... Does that make sense?

EDIT

If you wanted multiple joins you could have something like this...

List<Restaurant> result = (from c in db.Cities
                           join r in db.Restaurants on c.CityID equals r.CityID
                           join x in db.SomethingElse on r.SomethingID equals x.SomethingID
                           where c.CuisineName == cuisineName && c.CityID == cityID
                           select r).ToList();

---

LINQ To SQL doesn't support the Include() extension method, as in EF.

I suspect you're wanting .LoadWith() instead on the DataLoadOptions.

var db = new MyDataContext();
var dlo = new DataLoadOptions();
dlo.LoadWith<Cities>(p => p.Restaurants);
db.LoadOptions = dlo;

var restaurantList = from RESTAURANT in db.RESTAURANTs
                     where RESTAURANT.CITY.Any(t => t.CITY_ID == cuisineID)
                     select RESTAURANT;