Error when querying to a DbContext - entity-framework-6

Question

I'm working with EF CodeFirst. My classes are:
public class Persona
{
public int Id { get; set; }
public string Nombre { get; set; }
public string ApellidoUno { get; set; }
public string ApellidoDos { get; set; }
public virtual ICollection<Telefono> Telefonos { get; set; }
}
public class Telefono
{
public virtual int Id { get; set; }
public virtual string Numero { get; set; }
public virtual int IdPersona { get; set; }
public virtual Persona Persona { get; set; }
}
public class ContactoContexto : DbContext
{
public ContactoContexto()
: base("EF_Model")
{ }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<Persona>().ToTable("Personas");
// ... more Fluent API code.....
modelBuilder.Entity<Persona>()
.HasMany(x => x.Telefonos)
.WithRequired(x => x.Persona)
.HasForeignKey(x => x.IdPersona);
}
public DbSet<Persona> Personas { get; set; }
public DbSet<Telefono> Telefonos { get; set; }
}
And when I try to select some data, I get the following error:
Error 1 No se encontró una implementación del modelo de consulta para el tipo de origen 'EF_Model.ContactoContexto'. 'Where' no encontrado. c:\users\jmolina\documents\visual studio 2013\Projects\prueba EF general\3. ModeloNEgocio\ModeloNegocio.cs 27 39 3. ModeloNegocio
My code to select is:
public class Intento
{
public static IEnumerable<Persona> buscarcontactos(string nombre)
{
ContactoContexto conCon = new ContactoContexto();
var personas = (from p in conCon where p.nombre == nombre select p);
return personas;
}
}
What is wrong in my code?
Thanks in advance.
Jeronimo

Answer 1

When you're doing a Linq query in your context, you need to start from a DbSet. You should also instantiate the DbContext in a using statement to ensure that it gets properly disposed when you're done.
using (var conCon = new ContactoContexto())
{
var personas = (from p in conCon.Personas where p.Nombre == nombre select p);
// you need to use ToList() to actually materialize the result from the database
return personas.ToList();
}