ArcEngine实现多边形内部的挖洞操作

在一般的数据编辑流程中，有些时候可能会涉及到多边形内部的挖洞操作。在ArcEngine中，一般可以通过两种方式实现挖洞操作。一种是叠置分析，这主要是针对图层与图层之间的操作，我会在后续的博客中进行介绍，另一种则是用户自己绘制多边形实现挖洞操作，这主要是利用ITopologicalOperator接口进行实现。先来看一下效果图：

代码如下：

using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.DataSourcesFile;
using ESRI.ArcGIS.DataSourcesGDB;
using ESRI.ArcGIS.Display;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.Output;
using ESRI.ArcGIS.SystemUI;

namespace WindowsFormsApplication1
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();
            axMapControl1.LoadMxFile(@"E:\Users\dsf\Desktop\无标题.mxd");
        }

        // OnMouseDown事件
        private void axMapControl1_OnMouseDown(object sender, IMapControlEvents2_OnMouseDownEvent e)
        {
            IFeatureClass pFeatureClass = (axMapControl1.get_Layer(0) as IFeatureLayer).FeatureClass;
            IGeometry pGeometry = axMapControl1.TrackPolygon();
           
            // 空间过滤器
            ISpatialFilter pSpatialFilter = new SpatialFilter();
            pSpatialFilter.AddField("Shape");
            pSpatialFilter.Geometry = pGeometry;
            pSpatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelIntersects;

            // 要素游标
            IFeatureCursor pFeatureCursor = pFeatureClass.Search(pSpatialFilter, true);
            IFeature pFeature = pFeatureCursor.NextFeature();
            if (pFeature == null)
            {
                return;
            }

            // 遍历游标
            while (pFeature != null)
            {
                ITopologicalOperator pTopologicalOperator = pFeature.ShapeCopy as ITopologicalOperator;
                pFeature.Shape = pTopologicalOperator.Difference(pGeometry);
                pFeature.Store();
                pFeature = pFeatureCursor.NextFeature();
            }

            // 刷新地图
            System.Runtime.InteropServices.Marshal.ReleaseComObject(pFeatureCursor);
            axMapControl1.ActiveView.Refresh();
        }
    }
}