C#AE （4）几何形体及其操作

要求：

  编写程序，选中要素并对其进行Buffer，而后选中缓冲区内的要素。

 1、在地图上右键单击，根据鼠标位置查询到Parcels中的Parcel。在窗体上显示该Parcel的投影信息以及“Landuse”字段值。
 2、根据给定半径对1中的Parcel做缓冲区，并选中与缓冲区相交的所有parcel。

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作答：

1.点选要素，显示相关信息

 private void axMapControl1_OnMouseDown(object sender, ESRI.ArcGIS.Controls.IMapControlEvents2_OnMouseDownEvent e)
 {
	if (e.button == 2)
	{
		//////------------点选是根据鼠标点创建一个缓冲区，然后再用SelectByShape方法-------/////
		//创建鼠标点击的位置Point
		IPoint pPoint = new PointClass();
		pPoint.PutCoords(e.mapX, e.mapY); //PutCoords(X:Double,Y:Double)
	
		//创建缓冲区
		ITopologicalOperator pTO = pPoint as ITopologicalOperator;
		IGeometry pGeometry = pTO.Buffer(0); //半径为0点的缓冲区=点

		//选择Feature，IMap接口的方法SelectShape(Shape,env,justOne)
		//从Layer中依靠一个图形的范围shape和一个选择的环境来选择要素，在所有图层中只从IFeatureLayer的图层中进行选择
		axMapControl1.Map.SelectByShape(pGeometry, null, false);
		axMapControl1.Refresh(ESRI.ArcGIS.Carto.esriViewDrawPhase.esriViewGeoSelection, null, null);
		////////////----------------------------------------------------/////////////
	
		////////------------☆访问对Map中FeatureLayer被选中的要素----------------//////
		IFeatureLayer pFL = axMapControl1.Map.get_Layer(0) as IFeatureLayer;
		IFeatureClass pFC = pFL.FeatureClass;
		//使用了FeatureLayer类的IFeatureSelection接口，及接口的SelectionSet属性
		IFeatureSelection pFS = pFL as IFeatureSelection;
		ISelectionSet pSS = pFS.SelectionSet;
		//访问SelectionSet中的每个要素
		ICursor pCursor;
		pSS.Search(null, true, out pCursor);
		IFeatureCursor pFCur = pCursor as IFeatureCursor;
		IFeature pFea = pFCur.NextFeature();
	
		while (pFea != null)
		{
			textBox2.Clear();
			textBox3.Clear();
		
			IGeoDataset pGD = pFC as IGeoDataset;
			textBox2.Text = pGD.SpatialReference.Name.ToString();
			
			int FieldIndex = pFea.Fields.FindField("Landuse");
			if (pFea.get_Value(FieldIndex).ToString() != null)
				textBox3.Text = pFea.get_Value(FieldIndex).ToString();
			else
				textBox3.Text = "Land Use Unknown!";
	
			pFea = pFCur.NextFeature();
		}
	}
}

2.选中与缓冲区分析相交的要素

private void button1_Click(object sender, EventArgs e)
{
	IFeatureLayer pFL = axMapControl1.Map.get_Layer(0) as IFeatureLayer;
	IFeatureClass pFC = pFL.FeatureClass;
	
	//☆获取选中要素的属性(IMap.FeatureSelection方法获取Feature的属性信息)
	ISelection pSelection = axMapControl1.Map.FeatureSelection; //获取选择集
	IEnumFeatureSetup pEnumFS = pSelection as IEnumFeatureSetup; //打开属性标签
	pEnumFS.AllFields = true; 
	IEnumFeature pEnumF = pSelection as IEnumFeature; //读取属性
	IFeature pFea = pEnumF.Next();		

	if (pFea != null)
	{
		 axMapControl1.Map.ClearSelection(); //清空选择的要素
	
		//缓冲区
	 	IGeometry pGeometry = pFea.Shape
		ITopologicalOperator pTO = pGeometry as ITopologicalOperator;
	 	IGeometry pGeometry1 = pTO.Buffer(int.Parse(textBox1.Text));
	
		IFeatureSelection pFS = pFL as IFeatureSelection;
		
		ISpatialFilter pSF = new SpatialFilterClass();
		pSF.Geometry = pGeometry1;
		pSF.SpatialRel = esriSpatialRelEnum.esriSpatialRelIntersects; //地图中的是面要素
	
		pFS.SelectFeatures(pSF, esriSelectionResultEnum.esriSelectionResultNew, false);
		
		/* （优化代码，可以用上面的IFeatureSelectionn的SelectFeatures 替代 axMapControl1.Map.SelectFeaure）
		IFeatureCursor pFCur = pFC.Search(pSF, true);
		IFeature pFea1 = pFCur.NextFeature();
	
		while (pFea1 != null)
		{
			axMapControl1.Map.SelectFeature(pFL, pFea1); //选择要素；IMap接口的SelectFeature(Layer,Feature) 从Layer图层选择要素
		
			pFea1 = pFCur.NextFeature();
		} 
		*/
	}
	axMapControl1.ActiveView.Refresh();
}

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参考文章：
https://blog.csdn.net/m0_37768631/article/details/86037509