title: Get the current Workbook Object in C#
body: <p>I've been writing an application in C# which creates Custom Document properties in an Excel spreadsheet, I have a function for this which takes in a Workbook Object...</p>
  
  <p>However, actually getting the current Workbook object is proving to be quite annoying, I am using ExcelDNA to add functionality, however, I can't seem to pass my function a valid Workbook COM object.</p>