arcengine 开发几个注意释放内存的地方

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在循环、查询过程中经常出现如下错误：

1 、循环的游标一定要释放不然会报错。

   private void find_allroads_lxbm(IFeature feature_ld, string lxbm)        {            try            {                ISpatialFilter spatialfilter = new SpatialFilterClass();                spatialfilter.WhereClause = "[LXBM] = " + lxbm;                spatialfilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelIntersects;                //feature_ld该路段 feature_last下一路段                while (feature_ld != null)                {                    IPolyline polyline = feature_ld.Shape as IPolyline;                    //缓冲                    IPoint end_pt = polyline.ToPoint;                    ITopologicalOperator topo2 = end_pt as ITopologicalOperator;                    IGeometry geo_buffer_end = topo2.Buffer(1);                    spatialfilter.Geometry = geo_buffer_end;                    IFeatureCursor featcursor_lastld = m_featcls.Search(spatialfilter, true);                    IFeature feature_last = featcursor_lastld.NextFeature();                    try                    {                        while (feature_last != null)                        {                                                    /****省略***/                                                                         }                    }                    catch (Exception exx)                    {                                                MessageBox.Show(exx.ToString());                    }                                      //下一个                    feature_ld = feature_last;                                       System.Runtime.InteropServices.Marshal.ReleaseComObject(featcursor_lastld);                                   }                System.Runtime.InteropServices.Marshal.ReleaseComObject(spatialfilter);                ////垃圾回收                System.GC.Collect();                System.GC.WaitForPendingFinalizers();            }            catch (Exception exx)            {                MessageBox.Show(exx.ToString());            }                   }

2 关于查询（ISpatialFilter，IQueryFilter）：

 //该路线编码路段数量            IQueryFilter queryfilterall = new QueryFilterClass();            queryfilterall.WhereClause = " [LXBM]= "+ lxbm;            LDBM_MAXCOUNT = m_featcls.FeatureCount(queryfilterall);            //起始值            start_index = Convert.ToInt32(start_lxh);            IQueryFilter queryfilter = new QueryFilterClass();            queryfilter.WhereClause = " [LDBM]= "+ start_ldbm;            IFeatureCursor featcursor = m_featcls.Search(queryfilter, true);//最好是true

参考：http://www.cnblogs.com/gisoracle/archive/2012/01/28/2330541.html

为true分析：pFeatures集合存储了指向FeatureClass上所有Feature的引用，但是由于Recycling参数设置为TRUE也就是说每执行一个NextFeautre方法上一条记录的Feature值在内存中被回收，所以到最后遍历pFeatures集合的时候所有的IFeature引用指向的Feature对象都为Null。

未false分析：分析：pFeatures集合存储了指向FeatureClass上所有Feature的引用，但是由于Recycling参数设置为False也就是说每执行一个NextFeautre方法上一条记录的Feature值在内存中依然存在，所以到最后遍历pFeatures集合的时候所有的IFeature引用指向的Feature对象都依然存在。所以会执行的很Happy（如下图所示）：

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