excelapplication1.workbooks.open()怎么打开一个已经存在的工作簿，括号里的参数怎么写？(50分)

excelapplication1.workbooks.open()怎么打开一个已经存在的工作簿，括号里的参数怎么写？

最简单
Workbooks.Open(FileName);

复杂版本
Open( FileName, UpdateLinks, ReadOnly, Format, Password );
Excel : Variant;
FileName : String;
UpdateLinks : Integer;
ReadOnly : Boolean;
Format : Integer;
Password : ShortString;

excelapplication1.Workbooks.Open('文件',nil,false,nil,nil,nil,nil,nil,nil,nil,nil,nil,nil,0)

excelapplication1.Workbooks.Open('文件',nil,false,nil,nil,nil,nil,nil,nil,nil,nil,nil,nil,0)
好象不行，出现以下错误
[Error] Unit_Glxdh_Ktlx.pas(122): Incompatible types: 'OleVariant' and 'Pointer'
[Error] Unit_Glxdh_Ktlx.pas(122): Incompatible types: 'OleVariant' and 'Pointer'
[Error] Unit_Glxdh_Ktlx.pas(122): Incompatible types: 'OleVariant' and 'Pointer'
[Error] Unit_Glxdh_Ktlx.pas(122): Incompatible types: 'OleVariant' and 'Pointer'
[Fatal Error] QCManager.dpr(30): Could not compile used unit 'Unit_Glxdh_Ktlx.pas'

sorry,是NULL. 不好意思.

多人接受答案了。