Control printer output

edited January 2017 in General
Hi

is ther a way to control printer output, to check if label generated is
already printed or is in spooler?

I want to block the user to print again same label.

Thanks

Sergio Melchiori

Comments

  • edited January 2017
    Hi Sergio,

    See the following article on how to detect if a user printed to the
    printer. Once this occurs, you should be able to restrict the data your
    user has access to.

    http://www.digital-metaphors.com/rbWiki/Output/Printer/Detecting_Whether_Report_Printed_to_Printer

    Best Regards,

    Nico Cizik
    Digital Metaphors
    http://www.digital-metaphors.com
  • edited January 2017
    Sergio wrote:


    Years ago I had to do a similar thing in that I had to detect if:

    - the user actually sent output to printer, not to screen, file or
    archive
    - the user printed the entire range (not a sub range of pages)
    - the user did not cancel printing

    If all that was true, I had to assume it made it to the printer - that
    it was in the windows print spooler and would print ok.

    Because there were serious side effects if they printed the same
    document twice, when the printdialog closed I popped up a dialog box
    telling the user to "click ok if the printing succeeded, or cancel if
    printer jammed/failed".

    I never did bother to figure out if my print job successfully printed -
    I just made sure the end-users got used to waiting for the output!





    I had a TppReport in a form by itself (could/should have used
    datamodule)

    Here's the basic code I used for this:


    private
    FUserCancelled : Boolean; // did User Cancel print?
    FSentToPrinter : Boolean; // did report get sent to the
    printer, or just viewed/exported
    FPgSetting : TppPageSettingType;
    FPgRange : TppPageRangeType;



    //---EJB---2005.08.28-----------------------------
    procedure TfrmRepPSIView.ResetPrintStateFlags;
    begin
    FPgSetting := psFirstPage; // force to anything but "all" so we
    default to false
    FPgRange := prOddPages; // force to anything but "all" so we
    default to false
    FUserCancelled := False; // assume print not cancel
    FSentToPrinter := False; // assume not sent to printer
    end;

    procedure TfrmRepPSIView.ppReport1PrintDialogCreate(Sender: TObject);
    begin
    ResetPrintStateFlags; // reset again now because user can print,
    cancel, print again
    end;

    procedure TfrmRepPSIView.ppReport1PrintDialogClose(Sender: TObject);
    begin
    // we accept only sent to printer, but NOT if printtofile
    FSentToPrinter:= ( (ppReport1.PrintDialog.DeviceType='Printer') and
    not (ppReport1.PrintDialog.PrintToArchive) and
    not (ppReport1.PrintDialog.PrintToFile)
    );
    end;


    //---EJB---2005.08.28-----------------------------
    procedure TfrmRepPSIView.ppReport1Cancel(Sender: TObject);
    begin
    if ( Assigned(ppReport1.CancelDialog) and
    ppReport1.CancelDialog.Active and
    ppReport1.CancelDialog.Visible
    ) then FUserCancelled:=True;
    end;



    and called it with:

    frmRepPSIView.ResetPrintStateFlags;
    frmRepPSIView.ppReport1.Print;
    SentToPrinter := frmRepPSIView.WasSentToPrinterEx; // return
    whether or not this was sent to a printer
    DidUserCancel := frmRepPSIView.FUserCancelled; // return
    whether or not this print job got cancelled

    if ( SentToPrinter and (not DidUserCancel)) then
    if AskUserToWaitDialog then
    ...

    Cheers,
    EdB
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