DotSpatial 要素删除节点

/// <summary>
/// 要素删除节点
/// </summary>
/// <param name="selectedFeature">被选中的要素</param>
/// <param name="deleteCoord">节点坐标</param>

 private void DeleteVertex(IFeature selectedFeature, Coordinate deleteCoord)
        {
            if (selectedFeature == null)
            {
                return;
            }

            if (_layer.DataSet.FeatureType == FeatureType.Polygon)
            {
                _layer.EditMode = true;

                for (int prt = 0; prt < selectedFeature.Geometry.NumGeometries; prt++)
                {
                    IGeometry g = _selectedFeature.Geometry.GetGeometryN(prt);
                    Polygon poly = (Polygon)g;

                    #region 外环中查找

                    List<Coordinate> listCoorExtRing =poly.ExteriorRing.Coordinates.ToList<Coordinate>();

                    for (int ic = 0; ic < listCoorExtRing.Count; ic++)
                    {
                        if (listCoorExtRing[ic] == deleteCoord)
                        {
                            if (ic == 0 || ic == listCoorExtRing.Count - 1)//首节点被选中时，首末节点均删除
                            {
                                listCoorExtRing.RemoveAt(listCoorExtRing.Count - 1);
                                listCoorExtRing.RemoveAt(ic);

                                listCoorExtRing.Add(listCoorExtRing[0]);
                                break;
                            }
                            else
                            {
                                listCoorExtRing.RemoveAt(ic);

                                break;
                            }
                        }
                    }
                    //创建外环
                    LinearRing ringExterior = new LinearRing(listCoorExtRing.ToArray());

                    #endregion

                    #region 内环中查找

                    LinearRing[] ringInterior = null;
                    if (poly.NumInteriorRings > 0)
                    {
                        ringInterior = new LinearRing[poly.NumInteriorRings];

                        //遍历内环
                        for (int i = 0; i < poly.NumInteriorRings; i++)
                        {
                            List<Coordinate> listCoorIntRing =poly.GetInteriorRingN(i).Coordinates.ToList<Coordinate>();
                            //判断
                            for (int ic = 0; ic < listCoorIntRing.Count; ic++)
                            {
                                if (listCoorIntRing[ic] == deleteCoord)
                                {
                                    if (ic == 0 || ic == listCoorIntRing.Count - 1)//首节点被选中时，首末节点均删除
                                    {
                                        listCoorIntRing.RemoveAt(listCoorIntRing.Count - 1);
                                        listCoorIntRing.RemoveAt(ic);

                                        listCoorIntRing.Add(listCoorIntRing[0]);
                                        break;
                                    }
                                    else
                                    {
                                        listCoorIntRing.RemoveAt(ic);
                                        break;
                                    }
                                }
                            }

                            ringInterior[i] = new LinearRing(listCoorIntRing.ToArray());
                            listCoorIntRing = null;
                        }
                    }

                    #endregion

                    #region 要素Geometry更新
                                      
                    Polygon polyNew = null;
                    if (poly.NumInteriorRings > 0)//存在内环
                    {
                        polyNew = new Polygon(ringExterior, ringInterior);
                    }
                    else //仅存在外环
                    {
                        polyNew = new Polygon(ringExterior);
                    }

                    selectedFeature.Geometry = polyNew;

                    #endregion

                }
                _layer.DataSet.InvalidateVertices();
                _layer.DataSet.UpdateExtent();
                _layer.DataSet.Save();

                _layer.EditMode = false;

                Map.Invalidate();
            }
        }