Get shared pages using localized component - tridion

Question

I'm currently working on a event handler, which will on save-event, save the latest revision date of the page and it's components into a custom database, and this is working, but i'm facing some performance issues.
Let me give you an example, for how it's working:
If a component is saved/updated (changes are made), then I want to update all pages using this component in my custom database.
Basic blueprint setup:
200 contains components
400 translation publication for components (inherent components from 200)
500 master publication for pages
600 local site publication inherent components from 400 and pages from 500)
So lets say we have component X in 200, this component is included in in a page in 500, X is localized in 400 (let us call it X(l)) and the page in 600 is NOT localized ( i.e it will use the component x(l))
So now to my question:
In my save event handler, i check what pages X(l) are included in , by using :
var filter = new UsingItemsFilter(component.Session)
{
IncludeLocalCopies = true,
ItemTypes = new[] { ItemType.Page }
};
but this will only give me references to pages from 500.
So what i then do (which feels kind of stupid) is to
create a tcm id of all pages in child publications(by looping over them) that inherent this page (now im using some psuedocodelike coding):
foreach(var 500page in foundPages)
foreach(var publication in publications){
if(subject.Session.IsExistingObject(
new TcmUri(page.Id.ItemId,page.Id.ItemType,publication.Id.ItemId)
))
{
someListThatWillContainAllChildPagesFrom500.Add(TheAboveTcmUri);
}
}
And then for each page, check the components in that page, and finally save this state to my custom database.
So the question is, is there a way by to query for all pages, that make use of the localized component, by using the TOM.NET api (no not CoreServiceClient)?
Is there a better way to find child publications of a publication, so I only need to check for pages in the childPublication?
Br Martin

Answer 1

The following code sample should give you the shared items of a specific local/localized item along with the item. BluePrintNodesFilter was introduced in 2013, however in earlier version BluePrintFilter should work in similar way.
SystemManager systemManager = session.SystemManager;
BluePrintNodesFilter filter = new BluePrintNodesFilter(session)
{
BaseColumns = ListBaseColumns.Id,
ForItem = page
};
IEnumerable<BluePrintNode> allNodes = systemManager.GetBluePrintNodes(filter);
IEnumerable<RepositoryLocalObject> sharedAndLocal = (from node in allNodes
where node.Item != null
where node.Item.OwningRepository.Id == page.OwningRepository.Id
select node.Item).ToArray();