I have an EntityCollection<EntityBase2> full of entities of various types. I need to create an EntityView2 that filters just on a particular entity type.

Is there a built-in predicate to do this?

Cheers Simon

Hi,

As far i know, ther is no built-in predicate witch do that.

GetEntityTypeFilter() uses PK FK to filter on a particular entity type.

Maybe you can modify your schema to creat hierarchy...

simmotech wrote:

I have an EntityCollection<EntityBase2> full of entities of various types. I need to create an EntityView2 that filters just on a particular entity type.

Is there a built-in predicate to do this?

Cheers Simon

In v2.5 there is, we added a delegatepredicate, which simply executes the delegate you specify, so you can use that to filter on a particular type.

example of it in action:

[Test]
public void DelegatePredicateTest()
{
    EntityCollection<CustomerEntity> customers = new EntityCollection<CustomerEntity>();
    using(DataAccessAdapter adapter = new DataAccessAdapter())
    {
        adapter.FetchEntityCollection(customers, null);
    }

    Assert.AreEqual(91, customers.Count);
    // create a view from all customers which have a customername with length > 20 characters.
    EntityView2<CustomerEntity> customersWithLongName = new EntityView2<CustomerEntity>(customers,
                    new DelegatePredicate(delegate(IEntityCore toExamine) { return ((CustomerEntity)toExamine).CompanyName.Length > 20; }));
    Assert.AreEqual(30, customersWithLongName.Count);
}

If you're on v2.0 code, you can create it as well, using a derived class from Predicate, where you simply override InterpretPredicate. That's the method which is called when a predicate is used for in-memory filtering

Thanks for that - I was going to using DelegatePredicate but thought I was missing something obvious.

Since noone else else mentioned it in the forums, is this considered an unusual requirement?

Cheers Simon

simmotech wrote:

Thanks for that - I was going to using DelegatePredicate but thought I was missing something obvious.

Since noone else else mentioned it in the forums, is this considered an unusual requirement?

Cheers Simon

I haven't seen it much, but I can imagine it is a requirement sometimes, hence the reason the DelegatePredicate is there, to be able to easily filter sets on whatever aspect you want to filter on of the entity objects, e.g. type.