ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Desktop.Core Namespace / CustomItemBase Class / Fetch Method / Fetch() Method
Version

Fetch() Method
Custom items that are containers should implement fetch to populate their child items when they are expanded for the first time in Catalog.
Syntax
public virtual void Fetch()
Remarks
Child items should derive from CustomItemBase. Container items must create their own children and add them to their child collection via this.AddRangeToChildren(childItems)
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also