The id of the external project of the external data item to which a new reference has been added. 
   Namespace:   Autodesk.Revit.DB.Events  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 23.0.0.0 (23.1.0.0) 
  Since:  2023 
Syntax
| C# | 
|---|
   |  
| Visual Basic | 
|---|
   |  
| Visual C++ | 
|---|
   |