The index of the view being printed out of the set of all views being printed. 
   Namespace:   Autodesk.Revit.DB.Events  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0) 
  Since:  2010 
Syntax
Remarks
 The index is zero-based. When a single view is being printed, this value should be 0.