ArcGIS Pro 2.7 API Reference Guide
CreateLassoGraphicElement Method (IElementFactory)
Example 

ArcGIS.Desktop.Layouts Namespace > IElementFactory Interface : CreateLassoGraphicElement Method
Layout or GroupElement
Polygon
CIMPolygonSymbol
Creates a graphic lasso element on a layout from a single polygon geometry. This method must be called on the MCT. Use QueuedTask.Run.
Syntax

Parameters

elementContainer
Layout or GroupElement
polygon
Polygon
polygonSymbol
CIMPolygonSymbol

Return Value

Returns a GraphicElement.
Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
Remarks
If the element container is a Layout then the element gets added to the root level of the layout TOC at the top most position. If the element container is a GroupElement then it gets added to the group at the topmost position.
Example
//Create a graphic lasso element with simple line and fill styles.

//Construct on the worker thread
await QueuedTask.Run(() =>
{
  //Build geometry
  List<Coordinate2D> plyCoords = new List<Coordinate2D>();
  plyCoords.Add(new Coordinate2D(1, 1));
  plyCoords.Add(new Coordinate2D(1.25, 2));
  plyCoords.Add(new Coordinate2D(1.5, 1.1));
  plyCoords.Add(new Coordinate2D(1.75, 2));
  plyCoords.Add(new Coordinate2D(2, 1.1));
  plyCoords.Add(new Coordinate2D(2.25, 2));
  plyCoords.Add(new Coordinate2D(2.5, 1.1));
  plyCoords.Add(new Coordinate2D(2.75, 2));
  plyCoords.Add(new Coordinate2D(3, 1));
  Polygon poly = PolygonBuilder.CreatePolygon(plyCoords);

  //Set symbolology, create and add element to layout
  CIMStroke outline = SymbolFactory.Instance.ConstructStroke(ColorFactory.Instance.BlackRGB, 2.0, SimpleLineStyle.Solid);
  CIMPolygonSymbol polySym = SymbolFactory.Instance.ConstructPolygonSymbol(ColorFactory.Instance.RedRGB, SimpleFillStyle.ForwardDiagonal, outline);
  GraphicElement polyElm = LayoutElementFactory.Instance.CreatePolygonGraphicElement(layout, poly, polySym);
  polyElm.SetName("New Lasso");
});
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

IElementFactory Interface
IElementFactory Members