ArcGIS Pro 3.1 API Reference Guide
ArcGIS.Desktop.Core Namespace / Project Class / Items Property
Example Version

Items Property (Project)
Gets the current project's collection of project items
Syntax
Remarks

Returns the current collection of project items: the maps, layouts, toolboxes, databases, folder connections, locators, and so on that have been added to the project.

A folder connection is a project item. Subfolders and files accessed using a folder connection are items, but are not project items; they have not been added to a project. Similarly, databases that have been added to a project are project items, but databases accessed from a folder connection are items. The items within a database are always items, not project items.

Example
How to access Geoprocessing History
string openProjectPath = @"D\DATA\IGPHistoryItemTestProject\IGPHistoryItemTestProject.aprx";
await Project.OpenAsync(openProjectPath); 
MapProjectItem mapProjItem = Project.Current.GetItems<MapProjectItem>().FirstOrDefault(item => item.Name.Equals("Map", StringComparison.CurrentCultureIgnoreCase));

var map = await QueuedTask.Run(() => mapProjItem.GetMap());
var ftrLayer = map.Layers[0] as FeatureLayer;
string tool1 = "management.GetCount";     
var args1 = Geoprocessing.MakeValueArray(ftrLayer);
var env = Geoprocessing.MakeEnvironmentArray(overwriteoutput: true);          
GPExecuteToolFlags executeFlags = GPExecuteToolFlags.AddToHistory;
var t = await Geoprocessing.ExecuteToolAsync(tool1, args1,env,null,null,executeFlags);

IEnumerable<IGPHistoryItem> hisItems = Project.Current.GetProjectItemContainer(Geoprocessing.HistoryContainerKey) as IEnumerable<IGPHistoryItem>;        

String hitemID="";
String hitemToolPath="" ;
IGPResult hitemGPResult=null;
DateTime hitemTimeStamp;

foreach (var hitem in hisItems)
{
    // common IGPHistoryItem and Item properties
    hitemID = (hitem as Item).ID;
    hitemToolPath = hitem.ToolPath;
    hitemGPResult = hitem.GPResult;
    hitemTimeStamp = hitem.TimeStamp;
}

Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3.0 or higher.
See Also