ArcGIS Pro 3.0 API Reference Guide
ArcGIS.Desktop.Mapping Namespace / PopupContent Class / ObjectID Property

ObjectID Property (PopupContent)
Gets or sets the objectID associated with the pop-up. Can be -1 if the pop-up is not tied to a specific object id.
Syntax
public long ObjectID {get; set;}
Requirements

Target Platforms: Windows 11, Windows 10, Windows 8.1

ArcGIS Pro version: 3.0 or higher.
See Also