ISelectionTracker求助

<P>其中,pSelTracker is ISelectionTracker<BR>pResizePicElement is IPictureElement</P>
<P>Set pSelTracker = pResizePicElement.SelectionTracker<BR>            pSelTracker.ShowHandles = True</P>
<P>           Set pSelTracker.Display = PageLayoutControl1.ActiveView.ScreenDisplay<BR>            pSelTracker.Geometry = pResizePicElement.Geometry<BR>            pSelTracker.Draw PageLayoutControl1.ActiveView.ScreenDisplay, 0,<BR>esriTrackerDominant<BR>            PageLayoutControl1.ActiveView.PartialRefresh esriViewGraphics,<BR>Nothing, Nothing</P>
<P>但上述代码没有反映,不知道问题出在哪里?谁能简述一下ISelectionTracker的用法</P>
<P>谢谢<BR></P>