Flex :: Manually Dispatch A Collection Change Event?

I have a standard combobox that dispatches a collection event when the dataprovider finishes initializing:

my_cb.addEventListener( CollectionEvent.COLLECTION_CHANGE, getMyStuff );

Then I have a custom component that also has a dataProvider. How do I get it to dispatch a collection change event when its dataprovider finishes loading?From what I've read, I can't do it. Will dispatching a propertychangeevent work?

UPDATE:I have a custom component that I call 'SortingComboBox' but it is not a ComboBox at all; it extends Button and I set is dataProvider property to my arraycollection, model.product (which is an arraycollection). how I use the dataProvider in that component:

code

[Bindable]
private var _dataProvider : Object;
public function get dataProvider() : Object
{[code]..........

In the createChildren() method of this component, I use this:

BindingUtils.bindProperty(dropDown, "dataProvider", this, "dataProvider");

The dropDown is a custom VBox that I use to display labels.