function TForm1.IsFileInUse(fName: string): boolean;
var
HFileRes : HFILE;
begin
Result := false;
if not FileExists(fName) then exit;
HFileRes :=
CreateFile(pchar(fName),
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;
procedure TForm1.Button1Click(Sender: TObject);
begin
if IsFileInUse(Edit1.Text) then
application.MessageBox('使用中','信息',MB_ok+mb_iconinformation)
else
application.MessageBox('未使用','信息',MB_ok+mb_iconinformation)
end;