AE要素选择（点选和拉框选择…

原文地址：AE要素选择（点选和拉框选择） 作者：小马哥淡定

转自： http://www.cnblogs.com/gisak/archive/2011/03/30/2000297.html

选择一个要素或者一个要素集（FeatureSelection）的方法很多，如IMap：：SelectByShape、ILayer：：search、IFeatureSection：：SelectFeature等方法

主要用到的方法：

IMap接口的SelectFeature(Layer, Feature) （方法，从一个Layer中选择一个Feature）；

IMap接口SelectByShape(Shape, env, justOne) （方法，从Layer中依靠一个图形的范围shape和一个选择的环境env来选择要素，而在所有图层中只从IFeatureLayer的图层中进行选择）

IFeatureSelection接口SelectFeatures (Filter, Method, justOne ) （方法，根据指定的标准过滤器filter和方法，选择要素，第一个参数为QueryFilter类型的变量，第二个参数为esriSelectionResultEnum类型的变量，第三个参数为布尔型变量，通常为false）

IFeatureLayer接口Search (IqueryFilter, book ) （方法，创建一个游标去查询相应设置的过滤器的查询）

1 点选法获取要素

   废话少说先看代码：

View Code

private double ConvertPixelsToMapUnits(IActiveView pActiveView, double pixelUnits)
{
// Uses the ratio of the size of the map in pixels to map units to do the conversion
IPoint p1 = pActiveView.ScreenDisplay.DisplayTransformation.VisibleBounds.UpperLeft;
IPoint p2 = pActiveView.ScreenDisplay.DisplayTransformation.VisibleBounds.UpperRight;
int x1, x2, y1, y2;
pActiveView.ScreenDisplay.DisplayTransformation.FromMapPoint(p1, out x1, out y1);
pActiveView.ScreenDisplay.DisplayTransformation.FromMapPoint(p2, out x2, out y2);
double pixelExtent = x2 - x1;
double realWorldDisplayExtent = pActiveView.ScreenDisplay.DisplayTransformation.VisibleBounds.Width;
double sizeOfOnePixel = realWorldDisplayExtent / pixelExtent;
return pixelUnits * sizeOfOnePixel;
}
IMap pMap = axMapControl1.Map;
IActiveView pActiveView = pMap as IActiveView;
IFeatureLayer pFeatureLayer = pMap.get_Layer( 0 ) as IFeatureLayer;
IFeatureClass pFeatureClass = pFeatureLayer.FeatureClass;

// 设置点击点的位置
IPoint point = pActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(e.x, e.y);
ITopologicalOperator pTOpo = point as ITopologicalOperator;
double length;
length = ConvertPixelsToMapUnits(pActiveView, 4 );
IGeometry pBuffer = pTOpo.Buffer(length);
IGeometry pGeomentry = pBuffer.Envelope;
// 空间滤过器
ISpatialFilter pSpatialFilter = new SpatialFilterClass();
pSpatialFilter.Geometry = pGeomentry;
// 根据被选择要素的不同，设置不同的空间滤过关系
switch (pFeatureClass.ShapeType)
{
case esriGeometryType.esriGeometryPoint:
pSpatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelContains;
break ;
case esriGeometryType.esriGeometryPolyline:
pSpatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelCrosses;
break ;
case esriGeometryType.esriGeometryPolygon :
pSpatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelIntersects;
break ;

}
IFeatureSelection pFSelection = pFeatureLayer as IFeatureSelection;
pFSelection.SelectFeatures(pSpatialFilter,esriSelectionResultEnum.esriSelectionResultNew, false );
ISelectionSet pSelectionset = pFSelection.SelectionSet;
ICursor pCursor;
pSelectionset.Search( null , true , out pCursor);
IFeatureCursor pFeatCursor = pCursor as IFeatureCursor;
IFeature pFeature = pFeatCursor.NextFeature();
while (pFeature != null )
{
pMap.SelectFeature(pFeatureLayer,pFeature);
pFeature = pFeatCursor.NextFeature();
}
pActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphicSelection, null , null );
// 另外的改写：
pSpatialFilter.GeometryField = pFeatureClass.ShapeFieldName;
IQueryFilter pFilter = pSpatialFilter;
IFeatureCursor pFeatCursor = pFeatureLayer.Search(pFilter, false );
IFeature pFeature = pFeatCursor.NextFeature();
while (pFeature != null )
{
pMap.SelectFeature(pFeatureLayer,pFeature);
pFeature = pFeatCursor.NextFeature();
}
pActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphicSelection, null , null );

另外还有一种比较简单的点选方法：

 

View Code

IGeometry g = null ;
IEnvelope pEnv;
IActiveView pActiveView = axMapControl1.ActiveView;
IMap pMap = axMapControl1.Map;
pEnv = axMapControl1.TrackRectangle();
if (pEnv.IsEmpty == true )
{
ESRI.ArcGIS.Display.tagRECT r;
r.bottom = e.y + 5 ;
r.top = e.y - 5 ;
r.left = e.x - 5 ;
r.right = e.x + 5 ;
pActiveView.ScreenDisplay.DisplayTransformation.TransformRect(pEnv, ref r, 4 );
pEnv.SpatialReference = pActiveView.FocusMap.SpatialReference;
}
g = pEnv as IGeometry;
axMapControl1.Map.SelectByShape(g, null , false );
axMapControl1.Refresh(esriViewDrawPhase.esriViewGeoSelection, null , null );

 

2 拉框选择

View Code

IMap pMap = axMapControl1.Map;
IActiveView pActiveView = pMap as IActiveView;
IEnvelope pEnv = axMapControl1.TrackRectangle();
pMap.SelectByShape(pEnv, null , false );
pActiveView.PartialRefresh(esriViewDrawPhase.esriViewGeoSelection, null , null );