What is the best way to copy the data from EntityCollection<MyFirstEntity> to EntityCollection<MySecondEntity>.

The definitions of MyFirstEntity and MySecondEntity are almost identical except that MySecondEntity has some additional fields.

I'm thinking that it might be possible to do this with a projection but I can't find a direct example for this.

Right now, I'm creating an empty collection for MySecondEntity and then looping through EntityCollection<MyFirstEntity> and creating each entity for EntityCollection<MySecondEntity> in the loop. It doesn't seem like a great approach but it does work.

I'm interested in the best option for performance but also for coding simplicity.

You can use Linq2Objects to query the first collection, and return items of the second type.(Projection)

Can you give me a short code snippet? I'm not sure I understand what you are telling me.

jovball wrote:

Can you give me a short code snippet? I'm not sure I understand what you are telling me.

// fetch collection
var customers = new EntityCollection<CustomerEntity>();         
using (var adapter = new DataAccessAdapter())
{
    adapter.FetchEntityCollection(customers, null);
}

// copy results to another collection of a similar type
var customersExtended = new EntityCollection<CustomerExtended>();
customersExtended = new EntityCollection<CustomerExtended> 
                    (from c in customers
                        select new CustomerExtended
                        {
                            CustomerId = c.CustomerId,
                            CompanyName = c.CompanyName,
                            Country = c.Country,
                            SomeExraField1 = string.Format("Country : {0}", c.Country),
                            SomeExraField2 = string.Format("City : {0}", c.City)
                            // more fields...
                        });