The ID of the parameter displayed by the field. 
   Namespace:   Autodesk.Revit.DB  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0) 
  Since:  2013 
Syntax
Remarks
 Most field types require a parameter ID. Count, Formula, and Percentage fields don't have parameter IDs.