ArcGIS Pro 2.6 API Reference Guide
IGalleryItem Interface
Members 

ArcGIS.Desktop.Framework.Contracts Namespace : IGalleryItem Interface
Implement this interface for a gallery item class if the gallery needs to be displayed in the gallery customization dialog.
Syntax
public interface IGalleryItem 
Public Interface IGalleryItem 
Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

See Also

Reference

IGalleryItem Members
ArcGIS.Desktop.Framework.Contracts Namespace