CategoriesItem(BuiltInCategory) Property

public virtual Category this[
	BuiltInCategory categoryId
] { get; }

Public Overridable ReadOnly Property Item ( 
	categoryId As BuiltInCategory
) As Category
	Get

public:
virtual property Category^ Item[BuiltInCategory categoryId] {
	Category^ get (BuiltInCategory categoryId);
}

abstract Item : Category with get
override Item : Category with get

Unlike the method that obtains categories by name, this routine will obtain the handle even of built-in subcategories. Since 2016 it is advised to use either Category.​​​GetCategory(​Document, ​BuiltIn​Category) or Category.​​​GetCategory(​Document,​ ElementId)​ from Category class.