AE+C# 缓冲区的实现（GeoProcessor的用法）

最近在做一个地理信息系统，需要实现缓冲区分析的功能。在网上、参考书上参考别人的代码。发现了一个大bug，一直解决不了，遂奋战至凌晨三点半。终于解决啦~

先搭建窗体：

选择图层 ：comboBox1
缓冲距离 ：textBox1
输出路径 ：textBox2
确认：button1
取消：button2

（一）变量以及构造函数的的定义

        //变量的定义private IActiveView pActiveView;private AxMapControl mapControl;public Buffer(){InitializeComponent();}//构建含参构造函数，将主窗体的AxMapControl传进来public Buffer(AxMapControl mainMapControl):this(){mapControl = mainMapControl;pActiveView = mainMapControl.ActiveView;}//窗体加载private void Buffer_Load(object sender, EventArgs e){if (mapControl == null || pActiveView.FocusMap.LayerCount == 0){return;}IEnumLayer layers = pActiveView.FocusMap.get_Layers();layers.Reset();ILayer layer = layers.Next();while (layer != null){comboBox1.Items.Add(layer.Name);layer = layers.Next();}}//设置输出路径private void textBox2_MouseDown(object sender, MouseEventArgs e){//set the output layerSaveFileDialog saveDlg = new SaveFileDialog();saveDlg.CheckPathExists = true;saveDlg.Filter = "Shapefile (*.shp)|*.shp";saveDlg.OverwritePrompt = true;saveDlg.Title = "Output Layer";saveDlg.RestoreDirectory = true;saveDlg.FileName = (string)comboBox1.SelectedItem + "_buffer.shp";DialogResult dr = saveDlg.ShowDialog();if (dr == DialogResult.OK)textBox2.Text = saveDlg.FileName;}//取消private void button2_Click(object sender, EventArgs e){this.Close();}//获取图层源路径public static string getLayerPath(ILayer pLayer){IDatasetName pDatasetName = (pLayer as IDataLayer2).DataSourceName as IDatasetName;IWorkspaceName pWorkspaceName = pDatasetName.WorkspaceName;return pWorkspaceName.PathName + "\\" + pLayer.Name + ".shp";}//确认private void button1_Click(object sender, EventArgs e){double bufferDistance = Convert.ToDouble(textBox1.Text.Trim());if (bufferDistance == 0.0){MessageBox.Show("缓冲区距离有误！");return;}if (comboBox1.Text == string.Empty){MessageBox.Show("输入图层不能为空！");return;}if (textBox2.Text == string.Empty){MessageBox.Show("输出路径不能为空！");return;}int index = comboBox1.SelectedIndex;string name = getLayerPath(pActiveView.FocusMap.get_Layer(index));string outPath = textBox2.Text;//Geoprocessor对象的定义ESRI.ArcGIS.Geoprocessor.Geoprocessor pGp = new ESRI.ArcGIS.Geoprocessor.Geoprocessor();//以下两种情况下会报错。//GeoProcessor pGp = new GeoProcessor();//IGeoProcessor2 pGp = new GeoProcessorClass();pGp.OverwriteOutput = true; //允许运算结果覆盖现有文件，可无ESRI.ArcGIS.AnalysisTools.Buffer pBuffer = new ESRI.ArcGIS.AnalysisTools.Buffer();//获取缓冲区分析图层ILayer pLayer = pActiveView.FocusMap.get_Layer(index);IFeatureLayer featLayer = pLayer as IFeatureLayer;//IFeatureCursor cursor = featLayer.Search(null, false);//IFeature feaClass = cursor.NextFeature();pBuffer.in_features = featLayer;pBuffer.out_feature_class = outPath; //输出路径pBuffer.buffer_distance_or_field = bufferDistance; //缓冲区参数pBuffer.dissolve_option = "NONE"; //融合缓冲区重叠交叉部分，如果不融合填"ALL"pGp.Execute(pBuffer, null); //执行string pFolder = System.IO.Path.GetDirectoryName(outPath); //得到字符串中文件夹位置string pFileName = System.IO.Path.GetFileName(outPath); //得到字符串中文件名字mapControl.AddShapeFile(pFolder, pFileName); //往地图控件里添加文件mapControl.ActiveView.Refresh(); //激活窗口刷新this.Close();}

对于我上面提到的bug，就是在我在执行GeoProcessor.Excute()方法时，一直弹出以下错误：

昨天遇到这个问题，当时差点崩溃，因为查了一天资料，别人的用法都是这样。差点想重装VS。突然灵机一动，去对象浏览器里看了一下：

解决方法：
定义Geoprocessor对象时，要用：

ESRI.ArcGIS.Geoprocessor.Geoprocessor pGp = new ESRI.ArcGIS.Geoprocessor.Geoprocessor();

而不能直接用：

GeoProcessor pGp = new GeoProcessor();

补充:
在写这篇博客时，我又想到：是不是我加的引用不对？我昨天其实已经加了GeoProcessor的引用，后来发现没用到，就注释掉了，但是我发现：将GeoProcessor改成小写p的Geoprocessor，就不用那么麻烦了。

using ESRI.ArcGIS.Geoprocessor;

Geoprocessor GP = new Geoprocessor();

emmmm…一定要细心！

2021/4/12 更新：评论很多人要主窗体代码，更新一下。
ps.这个项目太久远了，当时很多技术和意识都不太成熟，用了很多公共变量，暂时没时间完善了，（先活过毕设），大家凑活看吧。

//主窗体界面的公共变量IExtractionOp extractOp = null;//提取分析对象IGeoDataset maskRaster = null;//掩膜数据集IGeoDataset inGeodataset = null;//输入数据集IGeoDataset outGeodataset = null;//输出数据集IFeatureLayer pTocFeatureLayer;//当前所选矢量图层IEngineEditor pEngineEditor = new EngineEditorClass();//启动或停止编辑IEngineEditTask pEngineEditTask = null;IEngineEditLayers pEngineEditLayers = null;IActiveView pActiveView = null;IRasterLayer pOutRasLayer;//输出栅格IRasterLayer pRasterLayer;//所选栅格IRaster raster;Color Color;ILayer pLayer = null;//被选中的图层private frmMapTips frmMapTips = null;//MapTipsstring filepath = System.AppDomain.CurrentDomain.SetupInformation.ApplicationBase;//获取应用程序的目录private ISelectionEnvironment selectionEnvironment;//定义接口对象来设置选择环境private IMap pMap = null;private string sMxdPath = Application.StartupPath;int flag = 0;//标志是否点击了“添加图名”int ind;//当前所选图层的序号

接下来是主窗体界面的无参构造函数

        public MainForm(){InitializeComponent();InitObject();//窗体初始化时新建接口对象，对象具有默认的选项设置值selectionEnvironment = new SelectionEnvironmentClass();}private void InitObject(){try{//ChangeButtonState(false);pEngineEditor = new EngineEditorClass();//实例化IEngineEditor接口类型的对象，表示启动或者停止编辑OperateMap.EngineEditor = pEngineEditor;//将该对象的值传到MapManager类中的同接口类型的变量pEngineEditTask = pEngineEditor as IEngineEditTask;//接口转换，将IEngineEditor接口转换为IEngineEditTask接口，设置编辑任务pEngineEditLayers = pEngineEditor as IEngineEditLayers;//接口转换，将IEngineEditor接口转换为IEngineEditLayers接口，设置编辑图层sMxdPath = OperateMap.getPath(sMxdPath) + "\\data\\edit.mxd"; ;//获取Mxd文件的路径if (mainMapControl.CheckMxFile(sMxdPath)){mainMapControl.LoadMxFile(sMxdPath);}pMap = mainMapControl.Map;pActiveView = mainMapControl.Map as IActiveView;//刷新视图}catch (Exception ex){MessageBox.Show(ex.Message);}}

调用时的代码：

        private void 缓冲区分析ToolStripMenuItem_Click(object sender, EventArgs e){Buffer bf = new Buffer(mainMapControl);bf.Show();}

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