How can I change an existing link annotation to have Invisible Rectangle?

Q: How can I change an existing annotation to have a Link Type of
Invisible Rectangle? I tried it all and I cannot seem to work around
this issue, any help is much appreciated.
A: You probably want to set the border width in annotation's border
style dictionary to zero. For example:

Annot.BorderStyle bs = annot.GetBorderStyle(); bs.width = 0;


annot.SetBorderStyle(new Annot.BorderStyle
(Annot.BorderStyle.Style.e_solid, 0, 0, 0));