Synopsis

public class UnreferencedObjectEventArgs : EventArgs {
// Public Constructors
   public UnreferencedObjectEventArgs( object o, string id);  
// Public Instance Properties
   public string UnreferencedId{get; } 
   public object UnreferencedObject{get; } 
}

This type is sent as a parameter to the UnreferencedObjectEventHandler when an unreferenced object is detected in the XML stream. Its UnreferencedId property contains the id attribute of the unreferenced object, the its UnreferencedObject property contains the actual unreferenced object, which can be cast to its known type if you wish to examine its properties directly.