利用IIdentify接口实现点选和矩形选择要素

IMap pMap;
IPoint pPoint;
pMap = axMapControl1.Map;
pPoint = axMapControl1.ToMapPoint(e.x, e.y);
IIdentify pIdentify;
pIdentify = (IIdentify)pMap.get_Layer(0);
IArray pIDArray;
IFeatureIdentifyObj pFeatIdObj;
IIdentifyObj pIdObj;

//点选
IEnvelope pEnv=new EnvelopeClass();
pEnv =axMapControl1.ActiveView.Extent;
pEnv.Height= 100;
pEnv.Width  = 100;
pEnv.CenterAt(pPoint);
pIDArray = pIdentify.Identify(pEnv);

//矩形选择
 //IEnvelope testIRectangleElement;
//testIRectangleElement = axMapControl1.TrackRectangle();
//pIDArray = pIdentify.Identify(testIRectangleElement);
//i = pIDArray.Count;
if (pIDArray != null)
{
    for (int i = 0; i <= pIDArray.Count; i++)
    {
        pFeatIdObj = (IFeatureIdentifyObj)pIDArray.get_Element(i);
        pIdObj = (IIdentifyObj)pFeatIdObj;
        pIdObj.Flash(axMapControl1.ActiveView.ScreenDisplay);
        //消息显示查询目标的信息
        MessageBox.Show("Layer:" + pIdObj.Layer.Name + "Feature:" + pIdObj.Name);
    }
}
else
{
    MessageBox.Show("No feature identified.");
}

}