Перехват очереди печати

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, WinSpool, Grids, ExtCtrls, StdCtrls, ShellApi, Printers, ComCtrls;
 
type
  TForm3 = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    Label1: TLabel;
    Timer1: TTimer;
    Label2: TLabel;
    ListBox1: TListBox;
    StringGrid1: TStringGrid;
    Memo2: TMemo;
    procedure Timer1Timer(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form3: TForm3;
 
implementation
 
{$R *.dfm}
 
 function GetCurrentPrinterHandle: THandle;
var
  Device, Driver, Port: array[0..255] of Char;
  hDeviceMode: THandle;
begin
  Printer.getPrinter(Device, Driver, Port, hDeviceMode);
  if not OpenPrinter(@Device, Result, nil) then
    RaiseLastWin32Error;
end;
 
function SavePChar(p: PChar): PChar;
const
  error: PChar = 'Nil';
begin
  if not Assigned(p) then
    Result := error
  else  
    Result := p;
end;
 
 
procedure TForm3.Timer1Timer(Sender: TObject);
type
  TJobs  = array [0..1000] of JOB_INFO_1;
  PJobs = ^TJobs;
 
var
  hPrinter: THandle;
  bytesNeeded, numJobs: Cardinal;
  i: integer;
  pJ: PJobs;
begin
  hPrinter :=GetCurrentPrinterHandle;
  try
    EnumJobs(hPrinter, 0, 1000, 1, nil, 0, bytesNeeded,
      numJobs);
    pJ := AllocMem(bytesNeeded);
    if not EnumJobs(hPrinter, 0, 1000, 1, pJ, bytesNeeded,
      bytesNeeded, numJobs) then
      RaiseLastWin32Error;
   // memo1.Clear;
    if numJobs <> 0 then
    //  memo1.Lines.Add('No jobs in queue')
    //else
     begin
     Label1.Caption:=SavePChar(pJ^[0].pPrinterName);
      if  pJ^[0].pPrinterName='Samsung SCX-3200 Series' //определяем принтер
      then label2.Caption:='принтер найден';
      for i := 0 to pred(numJobs) do
        memo1.Lines.Add('страниц: '+IntToStr(pJ^[i].TotalPages)+'|'+
          Format(' файл: %s, статус (%d): %s',
          [SavePChar(pJ^[i].pDocument),
          pJ^[i].Status, SavePChar(pJ^[i].pStatus)]));
          //StringGrid1.Cells[1,1]:=IntToStr(pJ^[i].TotalPages);
    for i := 0 to Pred(numJobs) do
    StringGrid1.Cells[1,1]:=IntToStr(pJ^[i].TotalPages);
    end;
 
  finally
    ClosePrinter(hPrinter);
  end;