procedure TForm1.Button1Click(Sender: TObject);
begin
  CEdit := TEdit.CreateParented(Application.Handle);
  CEdit.Parent := Application.MainForm;
  Hok := SetWindowsHookEx(WH_CALLWNDPROC,WNDProcHook,HInstance,GetCurrentThreadId);
  if PrintDialog1.Execute then
  begin
    ShowMessage(CEdit.Text);
  end;
  UnhookWindowsHookEx(HOK);
  FreeAndNil(CEdit);
end;

var
  DownBtnID: Integer;
  PrntDlgHandle: THandle;
  CEdit: TEdit;
function WNDProcHook(code: Integer; wparam: WPARAM; lparam: LPARAM): LRESULT stdcall;
var
  msg: PCWPSTRUCT;
  wNotifyCode,wID: Word;
  r,WinR: TRect;
  DwonBtnHandle: THandle;
begin
  if code < 0 then
    Result := CallNextHookEx(Hok, code, wparam, lparam)
  else
  begin
    msg := PCWPSTRUCT(lparam);
    case msg.message of
    WM_INITDIALOG:
       begin
          PrntDlgHandle := msg.hwnd;
          DwonBtnHandle := FindWindowEx(PrntDlgHandle,0,'Button','打印范围');
          Windows.SetParent(CEdit.Handle,DwonBtnHandle);
          GetWindowRect(DwonBtnHandle,WinR);
          CEdit.Visible := True;
          DwonBtnHandle := FindWindowEx(PrntDlgHandle,0,'Button','选定范围(&S)');
          CEdit.Enabled := SendMessage(DwonBtnHandle,BM_GETCHECK,0,0) = 1;
          GetWindowRect(DwonBtnHandle,r);
          DownBtnID := GetDlgCtrlID(DwonBtnHandle);
          CEdit.Left := r.Right - WinR.Left;
          CEdit.Top := r.Top - WinR.Top;
       end;
    WM_COMMAND:
       begin
          if msg.hwnd = PrntDlgHandle then
          begin
            wNotifyCode := HIWORD(Msg.wparam);
            wID := LOWORD(Msg.wParam);
            if wNotifyCode = BN_CLICKED then
            begin
              CEdit.Enabled := wID = DownBtnID
            end;
          end;
       end;
    WM_DESTROY:
       begin
         //UnhookWindowsHookEx(HOK);
         //Hok := 0;
         //FreeAndNil(CEdit);
       end;
    end;
    Result := 0;
  end;
end;