function GetFileDateTime(const FileName: TFileName): TDateTime;
var
FStruct: TOFSTRUCT;
wndFile: Integer;
begin
wndFile := OpenFile(PChar(FileName), FStruct, OF_SHARE_DENY_NONE);
Result := FileDateToDateTime(FileGetDate(wndFile));
CloseHandle(wndFile);
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
if Opendialog1.Execute then
label1.Caption := DateTimeToStr(GetFileDateTime(Opendialog1.FileName));
end;