delphi从EXCEL读取数据为什么总是出现method 'cell' net supported by automation object?(100分)

delphi从EXCEL读取数据为什么总是出现method 'cell' net supported by automation object?源码如下：

procedure TForm1.Button1Click(Sender: TObject);
var excelapp,myworkbooklevariant;
i,j:integer;
begin
try
excelapp:=createoleobject('excel.application');
myworkbook:=createoleobject('excel.sheet');
except
application.MessageBox('无法打开文件','',mb_ok+mb_iconstop);
exit;
end;
excelapp.visible:=true;
MyworkBook:= ExcelApp.workBooks.Open('d:/aaa.xls');
panel1.Caption:=myworkbook.cells[2,2].value;
panel2.Caption:=myworkbook.cells[2,3].value;
panel3.Caption:=myworkbook.cells[2,4].value;
end;

panel1.Caption:=myworkbook.Cells.Item[2,2];
如果还不行就在book后加个ActiveSheet.

MyworkBook是workbook，workbook没有cells属性？

还是不行啊

MyworkBook.ActiveSheet.cells.....

中了 ，谢谢这位朋友，为什么我非要加这么多东西？