有用delphi开发的吗？

<P>procedure TForm1.MapControl1MouseDown(ASender: TObject; button, shift, x,
  y: Integer; mapX, mapY: Double);
var
  envlp: IEnvelope;
  bIsEmpty: wordbool;
begin
  //在Mapcontrol上按下鼠标左键后做拉框操作，实现地图放大功能
  if (Button = 1) and (Shift = 0) then
  begin
    MapControl1.MousePointer := esriPointerZoomIn;
    MapControl1.Extent:=MapControl1.TrackRectangle ;</P>
<P>  //  envlp := MapControl1.TrackRectangle;
 //   envlp.Get_IsEmpty(bIsEmpty);
 //   if not bIsEmpty then
 //     MapControl1.Extent := envlp;
    exit;
  end;</P>

<P>运行后，当鼠标拉框后，出现“找不到成员“的错误，谁能帮我一把，谢谢！</P>

用activeview接口尝试下

楼主，有没有其它delphi源码，能不能贴点出来，让大家学学

<DIV class=quote><B>以下是引用<I>whereto</I>在2005-3-25 10:42:42的发裕?lt;/B>

<P>procedure TForm1.MapControl1MouseDown(ASender: TObject; button, shift, x,
  y: Integer; mapX, mapY: Double);
var
  envlp: IEnvelope;
  bIsEmpty: wordbool;
begin
  //在Mapcontrol上按下鼠标左键后做拉框操作，实现地图放大功能
  if (Button = 1) and (Shift = 0) then
  begin
    MapControl1.MousePointer := esriPointerZoomIn;
    MapControl1.Extent:=MapControl1.TrackRectangle ;</P>
<P>  //  envlp := MapControl1.TrackRectangle;
//   envlp.Get_IsEmpty(bIsEmpty);
//   if not bIsEmpty then
//     MapControl1.Extent := envlp;
    exit;
  end;</P>
<P>运行后，当鼠标拉框后，出现“找不到成员“的错误，谁能帮我一把，谢谢！</P>
</DIV>
<P>    MapControl1.activeView.extent:=MapControl1.DefaultInterface.TrackRectangle;</P></B>

<P>楼上的好人</P>

<P>var
  pWF:IWorkspaceFactory;
  pFW:IFeatureWorkspace;
  pFC:IFeatureClass;
  pGL:IGeoFeatureLayer;
  pSimpleRender:ISimpleRenderer;
  pFillSymbol:ISimpleFillSymbol;
  pOutlineSymbol:ISimpleLineSymbol;
begin
  pFillSymbol:=CoSimpleFillSymbol.create as ISimpleFillSymbol;
  pFillSymbol.Color:=g_display.GetRGBColor(235,202,250);</P><P>  pOutlineSymbol:=CoSimpleLineSymbol.create as ISimpleLineSymbol;
  pOutlineSymbol.Color:=g_display.GetRGBColor(0,0,0);
  pOutlineSymbol.Width:=1;</P><P>  pFillSymbol.Outline:=pOutlineSymbol;</P><P>  pSimpleRender:=CoSimpleRenderer.Create as ISimpleRenderer;
  pSimpleRender.Symbol:=Isymbol(pFillSymbol);
 result:=true;
 try
  pWF:=COShapefileWorkspaceFactory.create as IWorkspaceFactory;
  pFW:=pWF.OpenFromFile(mPath,Application.Handle) as IFeatureWorkspace;
  pFC:=pFW.OpenFeatureClass(mFileName);
  pGL:=CoFeatureLayer.create as IGeoFeatureLayer;
  pGL.Name:=pFC.AliasName;
  pGL.FeatureClass:=pFC;
  pGL.Renderer:=pSimpleRender as IfeatureRenderer;
  m_Map.AddLayer(pGL,0)
 except
 end;
end;</P><P>上面的代码有错误吗？高手指教一下</P>