AE要素选择（点选和拉框选择）
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
);