title: How to open files from office excel task pane add-in?
body: <p>I'm developing an Office Excel Task Pane add-in, and I have the need to import the content of external files (other spreadsheets and PDF files) into the active workbook.</p>
  
  <p>On VBA (also VB and C#), workbooks could be open with the Workbooks.Open() method, but it is not available on Office/Excel JS library.</p>
  
  <p>So, how may I open files from Office/Excel Task Pane add-ins?</p>
  
  <p>Thanks in advance!</p>