Two DbContexts using same models, error while saving

Question

I'm trying to get data from dbContext and save it to other dbContext. Actually, I want to import some data base on some validation from database A and store it to database B. I know there are other ways to do that but I want to it using EF with two DBContexts.

Here is the scenario: I've to DbContext class with names: T1Entities, InterfaceDbContext

these dbContext are using the same Models. Like I've a class with name orders and I'm using the same class for other of these context.

Like this way:

public partial class T1Entities : DbContext
{
    public virtual DbSet<Order> Orders { get; set; }
}

public class InterfaceDbContext : DbContext
{
    public DbSet<Order> Orders { get; set; }
}

and in my GetOrder function, I'm trying to get only those orders that are not present in InterfaceDbContext and trying to insert on that context.

public List<orders_mstr> GetOrders()
{
    // getting interface db Orders
    var interfaceOrders = _interfaceDb.Orders.ToList();

    // getting T1 db orders which are not present in it interface db
    var orders = _t1Db.Orders
                    .Where(o =>
                                interfaceOrders.All(x => x.id != o.id)
                    )
                    .ToList();


    // trying to save the first object.
    _interfaceDb.Orders.Add(orders[0]);
    _interfaceDb.SaveChanges();
}

I'm having exception here while saving:

An exception of type 'System.InvalidOperationException' occurred in EntityFramework.dll but was not handled in user code Additional information: An entity object cannot be referenced by multiple instances of IEntityChangeTracker.

Please note: I've to use the save Order class for other of the contexts. I know we can do that by creating different other class for each of these contexts.

Don't you need to detach the entities from the first context before adding them to the second? — stuartd, May 16 '17 at 16:00
Turn off proxy creation of the source context before retrieving the data, e.g. `_t1Db.Configuration.ProxyCreationEnabled = false; var orders = _t1Db.Orders....` — Ivan Stoev, May 16 '17 at 16:41

score 0 · Answer 1 · edited May 23 '17 at 12:34

0

From How do I detach objects in Entity Framework Code First?

var orders = _t1Db.Orders
    .AsNoTracking() // Query without tracking
    .Where(o =>
                interfaceOrders.All(x => x.id != o.id)
    )
    .ToList();

edited May 23 '17 at 12:34

Community

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answered May 16 '17 at 16:05

robaudas

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Two DbContexts using same models, error while saving

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