public sealed class MapProjectItem : ArcGIS.Desktop.Internal.Catalog.ProjectItemInfoCrawl, ArcGIS.Desktop.Core.IMetadata, ArcGIS.Desktop.Core.IProjectItem, ArcGIS.Desktop.Core.ISearchableItem, System.ComponentModel.INotifyPropertyChanged, System.IDisposable  

/// Get all the maps in a project
IEnumerable<MapProjectItem> projectMaps = Project.Current.GetItems<MapProjectItem>();

/// Remove a map from a project; the map is deleted
IProjectItem mapToRemove = Project.Current.GetItems<MapProjectItem>().FirstOrDefault(map => map.Name.Equals("OldStreetRoutes"));
var removedMapProjectItem = await QueuedTask.Run(
         () => Project.Current.RemoveItem(mapToRemove));

IEnumerable<MapProjectItem> newMapItemsContainer = project.GetItems<MapProjectItem>();

await QueuedTask.Run(() =>
{
  foreach (var mp in newMapItemsContainer)
  {
    //Do Something with the map. For Example:
    Map myMap = mp.GetMap();
  }
});

MapProjectItem mapProjItem = Project.Current.GetItems<MapProjectItem>().FirstOrDefault(item => item.Name.Equals("EuropeMap"));

//GetItems searches project content
var map = Project.Current.GetItems<MapProjectItem>().FirstOrDefault(m => m.Name == "Map1");
var layout = Project.Current.GetItems<LayoutProjectItem>().FirstOrDefault(m => m.Name == "Layout1");
var folders = Project.Current.GetItems<FolderConnectionProjectItem>();
var style = Project.Current.GetItems<StyleProjectItem>().FirstOrDefault(s => s.Name == "ArcGIS 3D");

//Find item uses a catalog path. The path can be to a file or dataset
var fcPath = @"C:\Pro\CommunitySampleData\Interacting with Maps\Interacting with Maps.gdb\Crimes";
var pdfPath = @"C:\Temp\Layout1.pdf";
var imgPath = @"C:\Temp\AddinDesktop16.png";

var fc = Project.Current.FindItem(fcPath);
var pdf = Project.Current.FindItem(pdfPath);
var img = Project.Current.FindItem(imgPath);

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;
}

//Create a map frame and set its camera by zooming to the extent of an existing bookmark.

//Construct on the worker thread
await QueuedTask.Run(() =>
{
  //Build 2D envelope geometry
  Coordinate2D mf_ll = new Coordinate2D(6.0, 8.5);
  Coordinate2D mf_ur = new Coordinate2D(8.0, 10.5);
  //At 2.x - Envelope mf_env = EnvelopeBuilder.CreateEnvelope(mf_ll, mf_ur);
  Envelope mf_env = EnvelopeBuilderEx.CreateEnvelope(mf_ll, mf_ur);

  //Reference map, create MF and add to layout
  MapProjectItem mapPrjItem = Project.Current.GetItems<MapProjectItem>()
                       .FirstOrDefault(item => item.Name.Equals("Map"));
  Map mfMap = mapPrjItem.GetMap();
  Bookmark bookmark = mfMap.GetBookmarks().FirstOrDefault(
                        b => b.Name == "Great Lakes");

  //At 2.x - MapFrame mfElm =
  //                  LayoutElementFactory.Instance.CreateMapFrame(
  //                                             layout, mf_env, mfMap);
  //         mfElm.SetName("New Map Frame");
  //
  MapFrame mfElm = ElementFactory.Instance.CreateMapFrameElement(
                       layout, mf_env, mfMap, "New Map Frame");

  //Zoom to bookmark
  mfElm.SetCamera(bookmark);
});

public static async Task<Map> FindOpenExistingMapAsync(string mapName)
{
  return await QueuedTask.Run(async () =>
  {
    Map map = null;
    Project proj = Project.Current;

    //Finding the first project item with name matches with mapName
    MapProjectItem mpi = proj.GetItems<MapProjectItem>()
      .FirstOrDefault(m => m.Name.Equals(mapName, StringComparison.CurrentCultureIgnoreCase));
    if (mpi != null)
    {
      map = mpi.GetMap();
      //Opening the map in a mapview
      await ProApp.Panes.CreateMapPaneAsync(map);
    }
    return map;
  });

}