EF type-safe include

Program.cs

using System;
using System.Data.Objects;
using System.Linq.Expressions;

namespace ConsoleApplication1
{
  public static class DatabaseEntitiesExtensions
  {
    public static ObjectQuery<T> Include<T, V>(this ObjectQuery<T> entities, Expression<Func<T, V>> expression)
    {
      var memberExp = expression.Body as MemberExpression;
      if (memberExp == null)
      {
        throw new ArgumentException();
      }
      
      var entityName = memberExp.Member.Name;
      return entities.Include(entityName);
    }
  }

  public class Program
  {
    static void Main(string[] args)
    {
      var context = new DatabaseEntities();
      var persons = context.Persons.Include(x => x.Department);

      foreach (var item in persons)
      {
        Console.WriteLine(item.PersonName + "," + item.Department.DepartmentName);
      }
    }
  }
}