使用IIdentify接口进行空间查询

利用ArcEngine空间查询，大多数人会马上想到利用IQueryFilter接口，的确，IQueryFilter接口是我们经常使用的查询接口而且使用比较简单，但是在大数据量查询数据，尤其是空间查询时效率会很低，导致速度会很慢。

 

给大家推荐一个接口，给刚刚入门或者还不知道该接口的朋友提供一点参考。

IIdentify

// IIdentify帮助介绍

The IIdentify interface can be used to identify features at the specified location. When this interface is on a map layer, the Identify method returns an array of FeatureIdentifyObject objects.

 

On a FeatureIdentifyObject, you can do a QI to the IIdentifyObj interface to get more information about the identified feature. The IIdentifyObj interface returns the window handle, layer, and name of the feature; it has methods to flash the feature in the display and to display a context menu at the Identify location.

IIdentify继承了FeatureLayer、RasterLayer、CadFeatureLayer等N种图层种类，而且查询效率比IQueryFilter要高

缺点：只有与查询图形相交一种查询方式没有IQueryfilter的查询方式多样

 

//获得查询图形

                IActiveView act = myMapControl.ActiveView.FocusMap as IActiveView;

                IPoint pp = act.ScreenDisplay.DisplayTransformation.ToMapPoint(X, Y);

 //QI FeatureLayer QI   IIdentif

                IIdentify pIdentify = needLayer as IIdentify;

                IArray pIDs = pIdentify.Identify((IGeometry)pp);

                if (pIDs == null || pIDs.Count == 0)

                {

                    return;

                }

                //取第一个实体

                IFeatureIdentifyObj pFeatIdObj = pIDs.get_Element(0) as IFeatureIdentifyObj;

// 1：获得IFeature对象

IFeature pFea= pFeatIdObj.Feature

myMapControl.FlashShape(needFeat.Shape, 3, 300, null);

//2：获得IRow对象

                IRowIdentifyObject pRowObj = pFeatIdObj as IRowIdentifyObject;

               IRow pRow= = pRowObj.Row ；