private IEnumerable <ID> DoGetChildIDs(ItemDefinition itemDefinition, CallContext context)
{
var headChildIDs = HeadProvider
.GetChildIDs(itemDefinition, context)?
.Cast <ID>().ToArray() ?? EmptyIds;
var readOnlyChildIDs = ReadOnlyProviders
.SelectMany(x => x
.GetChildIDs(itemDefinition)?
.Select(ID.Parse) ?? EmptyIds);
var childIDs = headChildIDs.Concat(readOnlyChildIDs) // .Join()
.GroupBy(x => x.Guid).Select(x => x.First()); // .Distinct()
// deleted or moved out items must be get off the list
var itemId = itemDefinition.ID;
foreach (var childID in childIDs)
{
var parentId = HeadProvider.GetParentID(new ItemDefinition(childID, string.Empty, ID.Null, ID.Null), context);
if (ReferenceEquals(parentId, null) || parentId == itemId)
{
yield return(childID);
}
}
}