Specifies the ID of the highest-level category to return, along with its subcategories. If no parent category is specified, all categories are returned for the specified site. (Please do not pass a value of 0; zero (0) is an invalid value for CategoryParent.) To determine available category IDs, call GetCategories with no filters and use a DetailLevel value of ReturnAll. If you specify multiple parent categories, the hierarchy for each one is returned.
See the
Field Index to learn which calls use CategoryParent.