ITopologicalOperator5 与ITopologicalOperator2的问题

<STRONG style="TEXT-ALIGN: left; LINE-HEIGHT: normal; FONT-STYLE: normal; WORD-WRAP: break-word; FONT-WEIGHT: bold">以下是ArcGIS10帮助的解释</STRONG><BR ><STRONG style="TEXT-ALIGN: left; LINE-HEIGHT: normal; FONT-STYLE: normal; WORD-WRAP: break-word; FONT-WEIGHT: bold">Note:</STRONG> the ITopologicalOperator2 interface has been superseded by<FONT style="LINE-HEIGHT: normal; WORD-WRAP: break-word" color=#810081>ITopologicalOperator5</FONT>.<BR ><BR >很明显应该ITopologicalOperator5应该可以替代ITopologicalOperator2，可是如下的语句在ITopologicalOperator5中运行错误，而在ITopologicalOperator2中就OK，不知道哪位高手遇到过。<BR ><BR >//通过拓扑简化检查是否有重复点<BR >ITopologicalOperator5 pTopo = pMPtCol as ITopologicalOperator5;<BR >pTopo.IsKnownSimple_2 = false;//这句出错了，在ITopologicalOperator2中OK<BR >pTopo.Simplify();