Need help for moving destination to the exact location of the document window on that page

Q: I have my own bookmark navigation tab in my application that should
replace the built-in navigation tab in 'pdftron.PDF.PDFViewCtrl'. Once
the bookmark is selected from the navigation we are setting current
page to the viewer and it displaying the page exactly
(pdfviewctrl.SetCurrentPage(page_no)).

But if the bookmark has children and this children also pointing to
the same page for another section, when we select the child bookmark
we don't know how to point to that exact section on the page.

For Example:
In a pdf document we have 2 pages, in the first page we have 3
sections. In my system we are displaying the bookmarks in the below
way:

Bookmark Navigation Tab
-----------------------
1. Introduction
    1.1 Introduction - A
    1.1 Introduction - B
    1.1 Introduction - C
2. Overview

If we select the "Introduction" bookmark, we are displaying the first
page in the viewer using this code
pdfviewctrl.SetCurrentPage(page_no).

But when we select the child bookmark, we would like to display the
exact section in the viewer (when we select "Introduction - A"
bookmark, it has to take me to that exact section on the first page).

I verified in our "PDFView" sample, it is taking me to the exact
section on the page. But we don't know how to do this in my
application

Could you please provide us a relevant sample for showing the exact
section to the child bookmark(s) on the page.

---------------------
A: Probably the simplest way to implement this behavior is using
PDFVIewCtrl.ExecuteAction():

Action action = bookmark.GetAction();
if (action.IsValid() && action.GetType() ==
pdftron.PDF.Action.Type.e_GoTo) {
  pdfview.ExecuteAction(action);
}

Using ExecuteAction your custom bookmark view will work the same way
as the built-in bookmark handler.

You can alternatively re-implement ExecuteAction() by getting the
Destination object from ' e_GoTo' action, extracting the optional
parameters from the destination array and showing the visible content
(e.g. using pdfview.ShowRect()).