C#AE练习（4）几何形体及其操作

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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。
在这里插入图片描述

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。

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PointIPoint 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();elsetextBox3.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.ShapeITopologicalOperator 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();
}