Update Note Geometry
VertexGeometry.cs
// Copyright 2011 ESRI
// 
// All rights reserved under the copyright laws of the United States
// and applicable international laws, treaties, and conventions.
// 
// You may freely redistribute and use this sample code, with or
// without modification, provided you include the original copyright
// notice and use restrictions.
// 
// See the use restrictions.
// 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using ESRI.ArcGISExplorer.Geometry;

namespace UpdateNoteGeometryCS
{
  // This class can be used to edit the vertices of single-part polygons and polylines, and also of multipoints.
  // If used to edit multipart polygons or polylines, only the first part is edited; the class can be extended to
  // edit multiparts.
  class VertexGeometry
  {
    private Polygon _pgon = null;
    private Polyline _pline = null;
    private Multipoint _mpt = null;

    public VertexGeometry(Geometry geom)
    {
      switch (geom.GeometryType)
      {
        case GeometryType.Polygon:
          _pgon = geom as Polygon;
          break;
        case GeometryType.Polyline:
          _pline = geom as Polyline;
          break;
        case GeometryType.Multipoint:
          _mpt = geom as Multipoint;
          break;
        default:
          throw new NotSupportedException();
      }
    }

    public Point GetPoint(int vertexIndex)
    {
      Point retVal = null;
      if (_pgon != null)
      {
        retVal = _pgon.GetPoint(vertexIndex);
      }
      else if (_pline != null)
      {
        retVal = _pline.GetPoint(vertexIndex);
      }
      else if (_mpt != null)
      {
        retVal = _mpt.GetPoint(vertexIndex);
      }
      return retVal;
    }

    public void SetPoint(int vertexIndex, Point newPoint)
    {
      if (_pgon != null)
      {
        _pgon.SetPoint(vertexIndex, newPoint);
      }
      else if (_pline != null)
      {
        _pline.SetPoint(vertexIndex, newPoint);
      }
      else if (_mpt != null)
      {
        _mpt.SetPoint(vertexIndex, newPoint);
      }
    }

    public int PointCount()
    {
      int retVal = -1;
      if (_pgon != null)
      {
        retVal = _pgon.PointCount(0);
      }
      else if (_pline != null)
      {
        retVal = _pline.PointCount(0);
      }
      else if (_mpt != null)
      {
        retVal = _mpt.PointCount;
      }
      return retVal;
    }
  }
}