Copy Entity Framework Object

Question

I have a EF4.1 class X and I want to make copy of that plus all its child records. X.Y and X.Y.Z

Now if I do the following it returns error.

The property \'X.ID\

Answer 1

In entity-framework-5, this is insanely easy with the DbExtensions.AsNotracking().

Returns a new query where the entities returned will not be cached in the DbContext or ObjectContext.

This appears to be the case for all objects in the object graph.

You just have to really understand your graph and what you do and don't want inserted/duplicated into the DB.

Lets assume we have objects like:

public class Person
{
  public int ID { get; set; }
  public string Name { get; set; }
  public virtual ICollection
 Addresses { get; set; }
}

public class Address
{
  public int ID { get; set; }
  public AddressLine { get; set; }
  public int StateID { get; set; }

  public ICollection { get; set; }
}

So in order to Duplicate a person, I need to duplicate the addresses, but I don't want to duplicate the States.

var person = this._context.Persons
  .Include(i => i.Addresses)
  .AsNoTracking()
  .First();

// if this is a Guid, just do Guid.NewGuid();
// setting IDs to zero(0) assume the database is using an Identity Column
person.ID = 0;

foreach (var address in person.Addresses)
{
  address.ID = 0;
}

this._context.Persons.Add(person);
this._context.SaveChanges();

If you then wanted to then reuse those same objects again to insert a third duplicate, you'd either run the query again (with AsNoTracking()) or detach the objects (example):

dbContext.Entry(person).State = EntityState.Detached;
person.ID = 0;
foreach (var address in person.Addresses)
{
  dbContext.Entry(address).State = EntityState.Detached;
  address.ID = 0;
}

this._context.Persons.Add(person);
this._context.SaveChanges();