asp.net mvc - MVC EF first result query is replaced by second result if second result got the same record -

i used entity framework 5. had table hotel had collection of roomtypes.

when wanted find hotel had following roomtypes looped function each roomtype , merged result. first result replaced second result if contained same record.

model public class hotel {   public int id { get; set; }   public string hotelname { get; set; }    [foreignkey("hotelid")]   public icollection<roomtype> roomtypes { get; set; } }  public class roomtype {   public int id { get; set; }   public string name { get; set; }   public int hotelid { get; set; } }  caller     public jsonresult gethotelbyroomtypes(string[] roomtypenames) {   list<list<hotel>> hotels = new list<list<hotel>>();   foreach (string roomtypename in roomtypenames) {     list<hotel> partialhotel = hotelrepo.gethotelsfromroomtype(roomtypename);     hotels.add(partialhotel);   }   return json(hotels); }   hotelrepo public list<hotel> gethotelsfromroomtype(string roomtype) {   list<roomtype> roomtypes = db.roomtypes.where(r => r.name.equals(roomtype)).tolist();   copy hotelid roomtypes int[] hotelids   list<hotel> hotels = db.hotels.where(h => hotelids.contains(h.id)).tolist();   return hotels  } 

my problem if sent 2 roomtypes ["deluxe", "suite"]. got list of hotela , hotelb first result. both of them contained collection of roomtype of "deluxe". after that, put these 2 hotels list>.

then second result returned hotela , hotelc hotela contained collection of roomtype "suite".

when happended, hotela of first result same hotela of second result held "suite" in roomtypes collection , "deluxe" in hotela missing.

do have suggestions?

use addrange method. can cleanup repo function.

public jsonresult gethotelbyroomtypes(string[] roomtypenames) {   list<list<hotel>> hotels = new list<list<hotel>>();   foreach (string roomtypename in roomtypenames) {     list<hotel> partialhotel = hotelrepo.gethotelsfromroomtype(roomtypename);     hotels.addrange(partialhotel);   }   return json(hotels); }  public list<hotel> gethotelsfromroomtype(string roomtype) {    list<hotel> hotelswithroomtype = db.hotels         .include(h => h.roomtypes)         .where(h => h.roomtypes.any(r => r.name.equals(roomtype))         .tolist();    return hotels;  } 

https://msdn.microsoft.com/en-us/library/z883w3dc%28v=vs.110%29.aspx?f=255&mspperror=-2147217396