ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Desktop.Mapping Namespace / Layer Class / Transparency Property
Version

Transparency Property (Layer)
Gets the transparency value set to the layer. 100 being fully transparent and 0 means opaque.
Syntax
public double Transparency {get;}
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also