Home/ Questions/Q 181799
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-11T14:49:37+00:00

Using Linq commands and Linq To SQL datacontext, Im trying to instance an Entity

  • 0

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_InformeMedico\app\InformeMedico.xaml.cs:línea 602        en Demo.View.InformeMedico.UpdateEstadoEstudio(Int32 codigo, Char state) en D:\cs_InformeMedico\app\InformeMedico.xaml.cs:línea 591        en Demo.View.InformeMedico.btnGuardar_Click(Object sender, RoutedEventArgs e) en D:\cs_InformeMedico\app\InformeMedico.xaml.cs:línea 683   InnerException:

Is that now allowed in LINQ2SQL?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 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.

    • 0