選擇一個要素或者一個要素集（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，從一個Layer中選擇一個Feature）；
IMap接口SelectByShape(Shape, env, justOne) （方法，從Layer中依靠一個圖形的範圍shape和一個選擇的環境env來選擇要素，而在所有圖層中只從IFeatureLayer的圖層中進行選擇）
IFeatureSelection接口SelectFeatures (Filter, Method, justOne ) （方法，根據指定的標準過濾器filter和方法，選擇要素，第一個參數爲QueryFilter類型的變量，第二個參數爲esriSelectionResultEnum類型的變量，第三個參數爲布爾型變量，通常爲false）
IFeatureLayer接口Search (IqueryFilter, book ) （方法，創建一個遊標去查詢相應設置的過濾器的查詢）
選擇一個要素或者一個要素集（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，從一個Layer中選擇一個Feature）；
IMap接口SelectByShape(Shape, env, justOne) （方法，從Layer中依靠一個圖形的範圍shape和一個選擇的環境env來選擇要素，而在所有圖層中只從IFeatureLayer的圖層中進行選擇）
IFeatureSelection接口SelectFeatures (Filter, Method, justOne ) （方法，根據指定的標準過濾器filter和方法，選擇要素，第一個參數爲QueryFilter類型的變量，第二個參數爲esriSelectionResultEnum類型的變量，第三個參數爲布爾型變量，通常爲false）
IFeatureLayer接口Search (IqueryFilter, book ) （方法，創建一個遊標去查詢相應設置的過濾器的查詢）
1 點選法獲取要素
廢話少說先看代碼：
{
// 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;
//設置點擊點的位置
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;
//空間濾過器
ISpatialFilter pSpatialFilter = new SpatialFilterClass();
pSpatialFilter.Geometry = pGeomentry;
//根據被選擇要素的不同，設置不同的空間濾過關係
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);
//另外的改寫：
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);
另外還有一種比較簡單的點選方法：
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 拉框選擇
IMap pMap = axMapControl1.Map;
IActiveView pActiveView = pMap as IActiveView;
IEnvelope pEnv = axMapControl1.TrackRectangle();
pMap.SelectByShape(pEnv, null, false);
pActiveView.PartialRefresh(esriViewDrawPhase.esriViewGeoSelection,null, null);