ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Desktop.Core Namespace / Project Class / AddItem Method
The Item to be added to the project
Example Version

AddItem Method (Project)
Adds the item to the current project. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public bool AddItem( 
   IProjectItem item
)

Parameters

item
The Item to be added to the project

Return Value

Returns a bool indicating whether or not the item was added successfully.
Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
Example
Add Folder to Project as IProjectItem
/// Add a folder connection to a project
Item folderToAdd = ItemFactory.Instance.Create(@"C:\Data\Oregon\Counties\Streets");
bool wasAdded = await QueuedTask.Run(() => Project.Current.AddItem(folderToAdd as IProjectItem));
Add GDBProjectItem to Project as IProjectItem
/// Add a file geodatabase or a SQLite or enterprise database connection to a project
Item gdbToAdd = folderToAdd.GetItems().FirstOrDefault(folderItem => folderItem.Name.Equals("CountyData.gdb"));
var addedGeodatabase = await QueuedTask.Run(() => Project.Current.AddItem(gdbToAdd as IProjectItem));
Importing Maps To Project
/// Import a mxd
Item mxdToImport = ItemFactory.Instance.Create(@"C:\Projects\RegionalSurvey\LatestResults.mxd");
var addedMxd = await QueuedTask.Run(
              () => Project.Current.AddItem(mxdToImport as IProjectItem));

/// Add map package      
Item mapPackageToAdd = ItemFactory.Instance.Create(@"c:\Data\Map.mpkx");
var addedMapPackage = await QueuedTask.Run(
              () => Project.Current.AddItem(mapPackageToAdd as IProjectItem));

/// Add an exported Pro map
Item proMapToAdd = ItemFactory.Instance.Create(@"C:\ExportedMaps\Election\Districts.mapx");
var addedMapProjectItem = await QueuedTask.Run(
              () => Project.Current.AddItem(proMapToAdd as IProjectItem));
Add a folder connection item to the current project
//Adding a folder connection
string folderPath = "@C:\\myDataFolder";
var folder = await QueuedTask.Run(() =>
{
  //Create the folder connection project item
  var item = ItemFactory.Instance.Create(folderPath) as IProjectItem;
  //If it is successfully added to the project, return it otherwise null
  return Project.Current.AddItem(item) ? item as FolderConnectionProjectItem : null;
});

//Adding a Geodatabase:
string gdbPath = "@C:\\myDataFolder\\myData.gdb";
var newlyAddedGDB = await QueuedTask.Run(() =>
{
  //Create the File GDB project item
  var item = ItemFactory.Instance.Create(gdbPath) as IProjectItem;
  //If it is successfully added to the project, return it otherwise null
  return Project.Current.AddItem(item) ? item as GDBProjectItem : null;
});
Import a pagx into a project
//Import a pagx into a project.

//Create a layout project item from importing a pagx file
await QueuedTask.Run(() =>
{
  IProjectItem pagx = ItemFactory.Instance.Create(
                            @"C:\Temp\Layout.pagx") as IProjectItem;
  Project.Current.AddItem(pagx);
});
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also