Entity Framework Code First

Hi,

I'm trying to write my first project for Entity Data Model with Code First approach.

My project is composed in 3 part:

EFDemo a console project
Demo.data a class library about my object model
Demo.dataAccess a class library  about my DbContext

The error viewable in the image attached, is not understandable for me.
Please  suggest me where to find the trouble

Thanks




namespace Demo.Data
{
    public class Attendee
    {
        [Key]
        private int AttendeeID { get; set; }
       
        [StringLength(50)]
        private string LastName { get; set; }

        private DateTime DateAddeted { get; set; }


    }
}

namespace Demo.DataAccess
{
    public class CodeContext : DbContext
    {
        public CodeContext() :
            base("Server=.;Database=CodeStock;Trusted_Connection=true")
        {      
   
        }    

        public DbSet<Attendee> Attendees { get; set; }
    }
}