ArcGIS Pro 2.8 API Reference Guide
IDString Property

ArcGIS.Desktop.Mapping Namespace > PopupContent Class : IDString Property
Gets or sets a "generic string feature id" associated with the pop-up. Can be empty if the pop-up is not associated with a feature using a string.
Syntax
public string IDString {get; set;}
Public Property IDString As String
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

PopupContent Class
PopupContent Members