30分在线等待（马上结帐）：怎么打开制定的excel文件？小问题啊！

Question

ExcelApplication1.Workbooks.Open (c:\a.xls
EmptyParam,EmptyParam,EmptyParam,EmptyParam,
EmptyParam,EmptyParam,EmptyParam,EmptyParam,
    EmptyParam,EmptyParam,EmptyParam,EmptyParam,0)；
我找到的是以上的，但不懂如何用！var
  str:string;
begin
if opendialog1.Execute then
begin
    str:=opendialog1.FileName;
    excelapplication1.Connect;
    excelapplication1.Visible[0]:=true;
    ExcelApplication1.Workbooks.Open(str)；
end;
这样做，ExcelApplication1.Workbooks.Open(str)；这里又出错！

Answer 1

procedure openExcel(filename:string);
var
  A,S:Variant;//application;sheet
begin
  try
    A:=createOleObject('Excel.Application');
    s:=CreateOleObject('Excel.Sheet');
  except
    showmessage('未安装MicroSoft Excel');
    Exit;
  end;
  A.WorkBooks.open(filename);
  A.visible:=true;
end;

Answer 2

excelapplication1.Workbooks.Open(opendialog1.FileName,null,null,null,null,null,null,null,null,null,null,null,null,0);
ExcelWorkbook1.ConnectTo(ExcelApplication1.Workbooks[1]);
ExcelWorksheet1.ConnectTo(ExcelWorkbook1.Worksheets[1] as _Worksheet);然后开始取数