问如何用EF填充我的基本客户

EN

 var bsCustomer1 = db.Customer.Where(p => p.CustomerID == 2)
        .Select(x => new CustomerBase
        {
            CustomerID = x.CustomerID,
            FirstName = x.FirstName,
            LastName = x.LastName,
            Address1 = x.Addresses.First(a => a.IsDefault).Address1,
            Address2 = x.Addresses.First(a => a.IsDefault).Address2,
            Phone = x.Addresses.First(a => a.IsDefault).Contacts.First(c => c.IsDefault).Phone),
            Fax = x.Addresses.First(a => a.IsDefault).Contacts.First(c => c.IsDefault).Fax)
        }).ToList();

1   Brett   X 1
2   Emily   X 2
4   Ryan    Y 1
10  Mark    Z 1 

1   Shirt
2   Dress

public partial class tePerson
{
    public int PersonId { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public Nullable<int> OrderId { get; set; }

    public virtual teOrder teOrder { get; set; }
}

public partial class teOrder
{
    public teOrder()
    {
        this.tePersons = new HashSet<tePerson>();
    }

    public int OrderId { get; set; }
    public string Description { get; set; }

    public virtual ICollection<tePerson> tePersons { get; set; }
}

public class OtherPerson
{
  public int PersonId { get; set; }
  public string PersonLongName { get; set; }
  public teOrder Order { get; set; }
}

static void Main(string[] args)
{
  using (var context = new TesterEntities())
  {
    //Say I just want to project a new object with a select starting from orders and then traversing up.  Not too hard
    var newObjects = context.teOrders.Where(order => order.OrderId == 1)
      //SelectMan will FLATTEN a list off of a parent or child in a one to many relationship
      .SelectMany(peopleInOrderOne => peopleInOrderOne.tePersons)
      .ToList()
      .Select(existingPerson => new OtherPerson
      {
        PersonId = existingPerson.PersonId,
        PersonLongName = $"{existingPerson.FirstName} {existingPerson.LastName}",
        Order = existingPerson.teOrder
      })
      .ToList();

    newObjects.ForEach(newPerson => Console.WriteLine($"{newPerson.PersonId} {newPerson.PersonLongName} {newPerson.Order.Description}"));

    // Just an action clause to repeat find items in my context, the important thing to note is that y extends teOrder which is another POCO inside my POCO
    Action<string, List<tePerson>> GetOrdersForPeople = (header, people) => 
    {
      Console.WriteLine(header);
      people.ForEach(person => Console.WriteLine($"{person.FirstName} {person.LastName} {person.teOrder.Description}"));
      Console.WriteLine();
    };

    //I want to look at a person and their orders.  I don't have to do multiple selects down, lazy loading by default gives me a child object off of EF
    GetOrdersForPeople("First Run", context.tePersons.ToList());


    //Say I want a new order for a set of persons in my list?
    var newOrder = new teOrder { Description = "Shoes" };
    context.teOrders.Add(newOrder);
    context.SaveChanges();

    //Now I want to add the new order
    context.tePersons.SingleOrDefault(person => person.PersonId == 1).teOrder = newOrder;
    context.SaveChanges();

    //I want to rexamine now
    GetOrdersForPeople("After changes", context.tePersons.ToList());

    //My newOrder is in memory and I can alter it like clay still and the database will know if I change the context
    newOrder.Description = "Athletic Shoes";
    context.SaveChanges();

    GetOrdersForPeople("After changes 2", context.tePersons.ToList());

    //Say I want to update a few people with new orders at the same time
    var peopleBesidesFirst = context.tePersons.Where(person => person.PersonId != 1).ToList();
    var firstPersonInList = context.tePersons.Where(person => person.PersonId == 1).ToList();

    var newOrders = new List<teOrder> {
      new teOrder { Description = "Hat", tePersons = peopleBesidesFirst },
      new teOrder { Description = "Tie", tePersons = firstPersonInList }
      };

    context.teOrders.AddRange(newOrders);
    context.SaveChanges();

    GetOrdersForPeople("After changes 3", context.tePersons.ToList());
  }

  Console.ReadLine();
}