linq to sql - Explicit construction of entity type '###' in query is not allowed.

Question

Using Linq commands and Linq To SQL datacontext, Im trying to instance an Entity called "Produccion" from my datacontext in this way:

Demo.View.Data.PRODUCCION pocoProduccion = 
(
    from m in db.MEDICOXPROMOTORs
    join a in db.ATENCIONs on m.cmp equals a.cmp
    join e in db.EXAMENXATENCIONs on a.numeroatencion equals e.numeroatencion
    join c in db.CITAs on e.numerocita equals c.numerocita
    where e.codigo == codigoExamenxAtencion
    select new Demo.View.Data.PRODUCCION
    {
         cmp = a.cmp,
         bonificacion = comi,
         valorventa = precioEstudio,
         codigoestudio = lblCodigoEstudio.Content.ToString(),
         codigopaciente = Convert.ToInt32(lblCodigoPaciente.Content.ToString()),
         codigoproduccion = Convert.ToInt32(lblNroInforme.Content.ToString()),
         codigopromotor = m.codigopromotor,
         fecha = Convert.ToDateTime(DateTime.Today.ToShortDateString()),
         numeroinforme = Convert.ToInt32(lblNroInforme.Content.ToString()),
         revisado = false,
         codigozona = (c.codigozona.Value == null ? Convert.ToInt32(c.codigozona) : 0),
         codigoclinica = Convert.ToInt32(c.codigoclinica),
         codigoclase = e.codigoclase,
    }
).FirstOrDefault();

While executing the above code, I'm getting the following error that the stack trace is included:

System.NotSupportedException was caught
  Message="The explicit construction of the entity type 'Demo.View.Data.PRODUCCION' in a query is not allowed."
  Source="System.Data.Linq"
  StackTrace:
       en System.Data.Linq.SqlClient.QueryConverter.VisitMemberInit(MemberInitExpression init)
       en System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node)
       en System.Data.Linq.SqlClient.QueryConverter.Visit(Expression node)
       en System.Data.Linq.SqlClient.QueryConverter.VisitSelect(Expression sequence, LambdaExpression selector)
       en System.Data.Linq.SqlClient.QueryConverter.VisitSequenceOperatorCall(MethodCallExpression mc)
       en System.Data.Linq.SqlClient.QueryConverter.VisitMethodCall(MethodCallExpression mc)
       en System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node)
       en System.Data.Linq.SqlClient.QueryConverter.Visit(Expression node)
       en System.Data.Linq.SqlClient.QueryConverter.VisitFirst(Expression sequence, LambdaExpression lambda, Boolean isFirst)
       en System.Data.Linq.SqlClient.QueryConverter.VisitSequenceOperatorCall(MethodCallExpression mc)
       en System.Data.Linq.SqlClient.QueryConverter.VisitMethodCall(MethodCallExpression mc)
       en System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node)
       en System.Data.Linq.SqlClient.QueryConverter.ConvertOuter(Expression node)
       en System.Data.Linq.SqlClient.SqlProvider.BuildQuery(Expression query, SqlNodeAnnotations annotations)
       en System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query)
       en System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression)
       en System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source)
       en Demo.View.InformeMedico.realizarProduccionInforme(Int32 codigoExamenxAtencion, Double precioEstudio, Int32 comi) en D:cs_InformeMedicoappInformeMedico.xaml.cs:línea 602
       en Demo.View.InformeMedico.UpdateEstadoEstudio(Int32 codigo, Char state) en D:cs_InformeMedicoappInformeMedico.xaml.cs:línea 591
       en Demo.View.InformeMedico.btnGuardar_Click(Object sender, RoutedEventArgs e) en D:cs_InformeMedicoappInformeMedico.xaml.cs:línea 683
  InnerException: 

Is that now allowed in LINQ2SQL?

Answer 1

Entities can be created outside of queries and inserted into the data store using a DataContext. You can then retrieve them using queries. However, you can't create entities as part of a query.