Namespace: BitMiracle.Docotic.Pdf
public bool Open { get; set; }
Public Property Open As Boolean Get Set
When a PdfOutlineItem is open, its immediate children in the hierarchy become visible on the screen; each child may in turn be open or closed, selectively revealing or hiding further parts of the hierarchy. When a PdfOutlineItem item is closed, all of its descendants in the hierarchy are hidden.
Any PdfOutlineItem without child items is always open. So, setting this property to false has no effect for items without child items.