c# - Entity Framework Code First - The entity or complex type cannot be constructed in a LINQ to Entities query -

first project using ef 6. have 3 tables, facility, ewc , facilitytoewc. each facility can have many ewc's.

public class facility {    public int facilityid { get; set; }    public string facilityname {get; set;} }  public class ewc {    public int ewcid { get; set; }    public sting ewccode { get; set;} }  public class facilitytoewc {     [key]     [databasegenerated(databasegeneratedoption.identity)]     public int facilitytoewcid { get; set; }      public int facilityid { get; set; }     public facility facility { get; set; }      public int ewcid { get; set; }     public ewc ewc { get; set; } } 

hope correct. problem need 1 method return each facility ewc codes in json format. have done

public class facilitydto  {     public int facilityid { get; set; }         public ienumerable<ewc> ewc { get; set; } }  public ienumerable<facilitydto> getfacilities() {    var result = (from currentfacility in db.facilities    select new facilitydto()    {       facilityid = currentfacility.facilityid,       ewc = ewcdetail in db.facilitytoewcs       ewcdetail.facilityid == currentfacility.facilityid       select new ewc { ewccode = ewcdetail.ewc.ewccode }    });    return result; } 

when execute above method error in posts title. appreciated. thanks.

i had create 2 tables , ef auto created mapping table once placed mappingcode in onmodelcreating. see code working below.

protected override void onmodelcreating(dbmodelbuilder modelbuilder)         {             modelbuilder.conventions.remove<pluralizingtablenameconvention>();             modelbuilder.entity<facility>()             .hasmany(x => x.ewc)             .withmany(x => x.facility)             .map(x =>             {                 x.totable("facilitytoewc");                 x.mapleftkey("facilityid");                 x.maprightkey("ewcid");             });              base.onmodelcreating(modelbuilder);         }  public class facility {    public int facilityid { get; set; }    public string facilityname {get; set;}     public icollection<ewc> ewc { get; set; } }  public class ewc {    public int ewcid { get; set; }    public sting ewccode { get; set;}    public icollection<facility> facility { get; set; }    }