判斷檔案是否被開啟

function TForm1.fn_FileInUse(sFileName:String):Boolean;
var HFileRes: HFILE;
begin
  Result := False;
  if not FileExists(sFileName) then
    exit;
  HFileRes := CreateFile(pchar(sFileName), GENERIC_READ or GENERIC_WRITE, 0, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
  Result := (HFileRes = INVALID_HANDLE_VALUE);
  if not Result then
    CloseHandle(HFileRes);
end;