http://www.scalabium.com/faq/dct0047.htm

D2007下未测试成功。

If you need detect how many jobs are in the MS Windows print spooler, then you must handle a WM_SPOOLERSTATUS message. When job is added or deleted in the spooler querue, this message will be broadcast.
So you must create a message handler for this message trapping:

type  TyourForm = class(TForm)  private    { Private declarations }    procedure WMSpoolerStatus(var Msg: TWMSpoolerStatus);      message WM_SPOOLERSTATUS;  public    { Public declarations }  end;implementation{$R *.DFM}procedure TyourForm.WMSpoolerStatus(var Msg: TWMSpoolerStatus);begin  ShowMessage(‘Now in the spooler a ‘ + IntToStr(msg.JobsLeft) + ‘ jobs‘;  msg.Result := 0;end;

通过消息获取 打印任务数量