ArcGIS Pro 2.9 API Reference Guide
MultipartBuilderEx Class
Members 

ArcGIS.Core.Geometry Namespace : MultipartBuilderEx Class
An abstract base class that is a pure .NET builder for creating a Polyline or a Polygon.
Object Model
MultipartBuilderEx ClassSegment ClassSpatialReference ClassGeometry Class
Syntax
public abstract class MultipartBuilderEx : GeometryBuilderEx 
Public MustInherit Class MultipartBuilderEx 
   Inherits GeometryBuilderEx
Remarks

Use the MultipartBuilderEx class to to create and/or modify a base Multipart shape. The builder is best suited for editing workflows where the user may be adding, inserting or removing parts of a Multipart geometry interactively. A Multipart is based upon the parent Geometry class. The Geometry class is immutable which means that you can not change its shape once it is created. Hence, the MultipartBuilderEx provides the way to make changes when working with a Multipart. Use the PolylineBuilderEx.ToGeometry or PolygonBuilderEx.ToGeometry method to get the Multipart from the builder.

The MultipointBuilderEx methods can be called on any thread.
Inheritance Hierarchy

System.Object
   ArcGIS.Core.Geometry.GeometryBuilderEx
      ArcGIS.Core.Geometry.MultipartBuilderEx
         ArcGIS.Core.Geometry.PolygonBuilderEx
         ArcGIS.Core.Geometry.PolylineBuilderEx

Requirements

Target Platforms: Windows 11, Windows 10, Windows 8.1

See Also

Reference

MultipartBuilderEx Members
ArcGIS.Core.Geometry Namespace