在mapcontrol中如何实现鹰眼功能？

在mapcontrol中如何实现鹰眼功能？

<P>朋友下面的代码，也许可以帮你！  </P><P>/// <summary>
  /// 根据主地图的边界值，改变当前地图的填充元素位置和大小
  /// </summary>
  public void DrawRectangle()
  {
   if( axMapControl.LayerCount > 0 )
   {
    // 删除地图中的所有绘制元素
    axMapControl.ActiveView.GraphicsContainer.DeleteAllElements();
    IElement pElement  = new RectangleElementClass();
    IFillShapeElement pFillShapeElement = pElement as IFillShapeElement;
    pFillShapeElement.Symbol = pFillSymbol;  
    pElement.Geometry = pActiveView.ScreenDisplay.DisplayTransformation.VisibleBounds;
  
    // 添加矩形元素到当前地图
    axMapControl.ActiveView.GraphicsContainer.AddElement( pElement, 0);
    axMapControl.CtlRefresh( esriViewDrawPhase.esriViewGraphics, pElement, axMapControl.Extent );
   }
  }</P><P>private void axMapControl_OnMouseDown(object sender, ESRI.ArcObjects.AxMapControl.IMapControlEvents2_OnMouseDownEvent e)
  {
   if( axMapControl.LayerCount > 0 )
   {
    IEnvelope pEnv = axMapControl.ActiveView.ScreenDisplay.DisplayTransformation.VisibleBounds;
    axMapControl.ActiveView.GraphicsContainer.DeleteAllElements();
    IEnvelope pEnvelope = new EnvelopeClass();
    IElement pElement  = new RectangleElementClass();
    IFillShapeElement pFillShapeElement = pElement as IFillShapeElement;
    pFillShapeElement.Symbol = pFillSymbol;  
    pEnvelope = axMapControl.TrackRectangle();
    if( pEnvelope.IsEmpty || pEnvelope.Width == 0.0 || pEnvelope.Height == 0.0)
    {
     // 移动当前主地图显示区域矩形的坐标调整
     IEnvelope pEnvelope1 = hook.ActiveView.ScreenDisplay.DisplayTransformation.VisibleBounds;  
     pEnvelope.XMin = e.mapX - (pEnvelope1.XMax - pEnvelope1.XMin) / 2;
     pEnvelope.XMax = e.mapX + (pEnvelope1.XMax - pEnvelope1.XMin) / 2;
     pEnvelope.YMin = e.mapY - (pEnvelope1.YMax - pEnvelope1.YMin) / 2;
     pEnvelope.YMax = e.mapY + (pEnvelope1.YMax - pEnvelope1.YMin) / 2;    
    }
    else
    {
    
     IEnvelope pEnvelope1 = hook.ActiveView.ScreenDisplay.DisplayTransformation.VisibleBounds;
     // 计算主地图显示区域矩形宽度与高度的比例
     double btWidth = pEnvelope1.Width / pEnvelope1.Height;
     // 判断划出矩形的边界值调整
     if( pEnvelope.Width > pEnvelope.Height * btWidth )
      pEnvelope.YMin = pEnvelope.YMax - pEnvelope.Width / btWidth;
     else
      pEnvelope.XMax = pEnvelope.XMin + pEnvelope.Height * btWidth;
    }   </P><P>    pElement.Geometry = pEnvelope;
    // 添加矩形元素到当前地图
    axMapControl.ActiveView.GraphicsContainer.AddElement( pElement, 0);
    axMapControl.CtlRefresh( esriViewDrawPhase.esriViewGraphics, pElement, axMapControl.Extent );</P><P>    // 改变主地图显示区域
    hook.ActiveView.ScreenDisplay.DisplayTransformation.VisibleBounds = pEnvelope;
    hook.ActiveView.Refresh();
   }
  }</P>

<img src="images/post/smile/dvbbs/em01.gif" /><img src="images/post/smile/dvbbs/em05.gif" />

<img src="images/post/smile/dvbbs/em06.gif" />

<img src="images/post/smile/dvbbs/em01.gif" />

<P>小弟我是新来的，看了很受益！谢谢！</P>