Delphi - 共享违规打开文本文件

I'm trying to open a text file for reading in a Delphi 7 app, but am getting I/O error 32 (sharing violation) because another application already has the file open. I've tried setting FileMode to "fmOpenRead or fmShareDenyNone" but now realise this doesn't apply to text files anyway.I'm trying to open a text file for reading in a