Panel);
        DrawPanel(ThumbBmp.Canvas,7,7+ThumbBmpTop,64,ThumbBmpHeight+1,LoweredPanel);
        ThumbBmp.Canvas.StretchDraw(Rect(8,8+ThumbBmpTop,71,8+ThumbBmpTop+ThumbBmpHeight),OriginalBmp);
        imagelist1.Add(ThumbBmp,nil);
      end;

      with ListView1.Items.Add  do
      begin
        ImageIndex:=imagelist1.Count-1;
        caption:=ImageFileList.GetCurFileName;
      end;
      ProgressBar1.Position:=i;
      application.ProcessMessages;
    end;
  finally
    listview1.Items.EndUpdate;
    ProgressBar1.Visible:=false;
  end;
  screen.Cursor:= crDefault;
  IsRefreshImageFinished:=true;

end;

7.过程DrawPanel的代码如下：

//在canvas上画一个Panel
procedure DrawPanel(canvas:TCanvas;Left,Top,Width,Height:integer;PanelType:integer);
var
  Right,Bottom:integer;
  LeftTopColor,RightBottomColor:TColor;
begin
  //凸起的panel
  if PanelType=RaisedPanel  then
  begin
    LeftTopColor:=clwhite;
    RightBottomColor:=clgray;
  end
  else //凹下去的panel
  begin
    LeftTopColor:=clgray;
    RightBottomColor:=clwhite;
  end;
      Right:=Left+width;
      Bottom:=Top+Height;

      Canvas.Pen.Width:=1;
      Canvas.Pen.Color:=LeftTopColor;

      Canvas.MoveTo(Right,Top);
      Canvas.lineTo(Left,Top);

      Canvas.LineTo(Left,bottom);

      Canvas.Pen.Color:=RightBottomColor;

      Canvas.lineTo(Right,Bottom);
      Canvas.lineTo(Right,Top);
end;
 8.接下来我们在ListView1的OnSelectItem事件里添加代码：

procedure TForm1.ListView1SelectItem(Sender: TObject; Item: TListItem;
  Selected: Boolean);
begin
  //当ShellTreeView1目录改变时 会激发此事件，
  if listview1.SelCount=0 then exit;

  //当窗体释放时也会激发此事件
  //ImageFileList.GetFileCount=0 后再 ImageFileList.SetIndex(item.Index);
  //会引起异常
  if ImageFileList.GetFileCount=0 then  exit;

  ImageFileList.SetIndex(item.Index);
  ShowPreImageFit(ImageFileList.GetCurFullFileName);
end;

9.其中过程ShowImageFit的代码比较罗嗦，如下所示：

//image1在Panel1中居中显示图片文件ImageFileName

procedure TForm1.ShowPreImageFit(const ImageFileName: string);
begin
  Image1.Visible:=false;
  if IsJpgFile(ImageFileName) then
  begin
    JpgToBmp(ImageFileName,PreViewJpg,PreViewBmp);
    Image1.Picture.Bitmap:=PreViewBmp;
  end
  else