关于offset c #下的实现！

<P>为什么在c#下面 offset 功能就消失了？？？ </P>
<P>MapObjects2.Rectangle  rect = new MapObjects2.RectangleClass ();
      double  rx = ((MapObjects2.Point )drr["shape"]).X ;
      double  ry = ((MapObjects2.Point )drr["shape"]).Y ;
    
      rect = axMap.Extent ;
      MapObjects2.Point  cpt = rect.Center;</P>
<P>      double dx = rx-cpt.X ;
      double dy = ry-cpt.Y;</P>
<P>      rect.Offset (dx,dy);   </P>
<P>      axMap.Extent = rect.Extent  ;

      axMap.Update ();</P>

<P>哪里出错了啊？？ 求救了~~`</P><img src="images/post/smile/dvbbs/em02.gif" /><img src="images/post/smile/dvbbs/em02.gif" />