EF6: Reusable ViewModel Mapping

Question

Using Entity Framework 6, I have display functions between Model objects and viewmodel objects contained in such a class:

public class DataMappers
{
    public static Expression<Func<Data.Models.Employer, EmployerViewModel>> EmployerMapper = (e => new EmployerViewModel()
    {
        Name = e.Name,
        Location = e.Location
        ....
    });
}

What can I then call in several places:

            results = db.Employers.OrderBy(e => e.Name)
                                  .Select(DataMappers.EmployerMapper)
                                  .ToList();

Which will generate the SQL statement only with the columns that I need. My question is, is there anyway to reuse this if other tables link to my Employer table? i.e.

    public static Expression<Func<Data.Models.Person, PersonViewModel>> Person = (p => new PersonViewModel()
    {
        FirstName = p.FirstName,
        LastName = p.LastName,
        Employer = *use the 'EmployerMapper' expression above on p.Employer*
        ....
    });

Can this be done, or will I need to duplicate this display code in every situation like this?

I tried to use it only as Funcinstead of Expression<Func>in this second example, which would compile ( Employer = EmployerMapper(p.Employer)), however at runtime you get an exception The LINQ expression node type 'Invoke' is not supported in LINQ to Entities.

Answer 1

LinqKit AsExpandable():

using LinqKit;

results = db.Employers.AsExpandable()
                      .OrderBy(e => e.Name)
                      .Select(DataMappers.EmployerMapper)
                      .ToList();

:

using LinqKit;

public static Expression<Func<Data.Models.Person, PersonViewModel>> Person = (p => new PersonViewModel()
    {
    FirstName = p.FirstName,
    LastName = p.LastName,
    Employer = DataMappers.EmployerMapper.Invoke(p.Employer)
    });

LinqKit , .