ArcGIS Pro 2.9 API Reference Guide
IProjectItem Interface
Members  Example 

ArcGIS.Desktop.Core Namespace : IProjectItem Interface
Provides basic interface for all project items
Object Model
IProjectItem InterfaceProjectItemInfo Class
Syntax
public interface IProjectItem 
Public Interface IProjectItem 
Remarks
Any class that is a type of project item must implement IProjectItem. These classes also follow a convention that includes "ProjectItem" as part of their name
Example
//create a new FolderConnectionProjectItem
var folderLocationItem = ItemFactory.Instance.Create(@"C:\temp\mydata");
await QueuedTask.Run(() => Project.Current.AddItem(folderLocationItem as IProjectItem);
Requirements

Target Platforms: Windows 11, Windows 10, Windows 8.1

See Also

Reference

IProjectItem Members
ArcGIS.Desktop.Core Namespace