基于C#的ArcEngine二次开发教程（13）：点、线、面要素的绘制 |
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基于C#的ArcEngine二次开发教程（13）：点、线、面要素的绘制
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目录 1 利用ArcMap绘制点、线和面的操作 1.1 绘图工具，绘制临时要素 1.2 在矢量图层中直接添加要素的方法 2 以Element的方式加入点要素 2.1 IGraphicsContainer 2.2 IElement 2.3 IGeometry 2.4 点元素添加实现源码 3 以Element形式添加线元素 3.1 IPolyline接口 3.2 IPointCollection接口 3.3 源码实现 4 以Element形式添加线元素 4.1 PolygonClass 4.2 源码实现 5 以矢量要素的形式添加点线面 5.1 点要素的添加 5.2 线要素的添加 5.3 面要素添加 1 利用ArcMap绘制点、线和面的操作 1.1 绘图工具，绘制临时要素添加Element图形元素，它仅保存在内存中，相当于以Map为画布，进行绘制的；软件关闭之后就会消失
在矢量图层中添加Feature要素，添加到矢量数据，并永久保存到硬盘中 图形容器接口，用于存放临时的点线面要素数据 接口介绍见缓冲区分析博文 2.2 IElement以下三个类均对该接口进行了实现
类Point对其进行了实现
同时也实现了IPoint类，满足接口跳转的条件
（1）定义全局变量 IPoint pt; IElement gele;（2）添加axMapControl1_OnMouseDown事件，用于记录鼠标点下的位置坐标 private void axMapControl1_OnMouseDown(object sender, IMapControlEvents2_OnMouseDownEvent e) { pt = new PointClass(); pt.X = e.mapX; pt.Y = e.mapY; gele = new MarkerElementClass(); gele.Geometry = pt as IGeometry; //生成线 }（3）添加点要素 private void 添加点元素ToolStripMenuItem_Click(object sender, EventArgs e) { IGraphicsContainer igc = axMapControl1.Map as IGraphicsContainer; igc.AddElement(gele, 0); axMapControl1.Refresh(); } 3 以Element形式添加线元素 3.1 IPolyline接口
 3.2 IPointCollection接口
（1）定义全局变量 IPointCollection lineCollect;//添加点集合; IPoint linePts;（2）Form1_Load创建IPointCollection接口实例对象 private void Form1_Load(object sender, EventArgs e) { lineCollect = new PolylineClass();//添加线元素 }（3）添加axMapControl1_OnMouseDown事件，用于记录鼠标点下的位置坐标 private void axMapControl1_OnMouseDown(object sender, IMapControlEvents2_OnMouseDownEvent e) { //生成线 linePts = new PointClass(); linePts.X = e.mapX; linePts.Y = e.mapY; //object a = Type.Missing; lineCollect.AddPoint(linePts);//添加多个点到点集合中 }（4）添加线要素 private void 添加线元素ToolStripMenuItem_Click(object sender, EventArgs e) { IGraphicsContainer igc = axMapControl1.Map as IGraphicsContainer; IElement lineEle = new LineElementClass(); IPolyline pline = new PolylineClass(); pline = lineCollect as IPolyline; lineEle.Geometry = pline as IGeometry; igc.AddElement(lineEle, 0); axMapControl1.Refresh(); } 4 以Element形式添加线元素 4.1 PolygonClass继承接口 （1）定义全局变量 //面 IPointCollection ploygonCollect;//添加点集合; IPoint ploygonPts;（2）Form1_Load创建IPointCollection接口实例对象 private void Form1_Load(object sender, EventArgs e) { ploygonCollect = new PolygonClass(); }（3）添加axMapControl1_OnMouseDown事件，用于记录鼠标点下的位置坐标 private void axMapControl1_OnMouseDown(object sender, IMapControlEvents2_OnMouseDownEvent e) { //生成面 ploygonPts = new PointClass(); ploygonPts.X = e.mapX; ploygonPts.Y = e.mapY; //object a = Type.Missing; ploygonCollect.AddPoint(ploygonPts); }（4）添加面要素 private void 添加面元素ToolStripMenuItem_Click(object sender, EventArgs e) { IGraphicsContainer igc = axMapControl1.Map as IGraphicsContainer; IElement polygonele = new PolygonElementClass(); IPolygon polyg = new PolygonClass(); polyg = ploygonCollect as IPolygon; polygonele.Geometry = polyg as IGeometry; igc.AddElement(polygonele, 0); axMapControl1.Refresh(); } 5 以矢量要素的形式添加点线面 5.1 点要素的添加 private void 添加点到矢量图层ToolStripMenuItem_Click(object sender, EventArgs e) { IFeatureLayer felyer = axMapControl1.get_Layer(0) as IFeatureLayer; IFeatureClass feclass = felyer.FeatureClass; IFeature fea = feclass.CreateFeature();//点要素的创建 fea.Shape = pt as IGeometry; fea.Store();//点要素的存储 axMapControl1.Refresh(); } 5.2 线要素的添加 private void 添加线到矢量图层ToolStripMenuItem_Click(object sender, EventArgs e) { IFeatureLayer felyer = axMapControl1.get_Layer(0) as IFeatureLayer; IFeatureClass feclass = felyer.FeatureClass; IFeature fea = feclass.CreateFeature(); IPolyline pline = new PolylineClass(); pline = lineCollect as IPolyline; fea.Shape = pline as IGeometry; fea.Store(); axMapControl1.Refresh(); } 5.3 面要素添加 private void 添加面到矢量图层ToolStripMenuItem_Click(object sender, EventArgs e) { IFeatureLayer felyer = axMapControl1.get_Layer(0) as IFeatureLayer; IFeatureClass feclass = felyer.FeatureClass; IFeature fea = feclass.CreateFeature(); IPolygon polygon = new PolygonClass(); polygon = ploygonCollect as IPolygon; fea.Shape = polygon as IGeometry; fea.Store(); axMapControl1.Refresh(); } |
通过接口IPolyline定义的Polyline类对象可以在接口IGeomtry、和IPointCollection之间跳转
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