Error in ppPDlg

rbuser

Hi,
I think that is error in unit ppPDlg in procedure
TppPrintDialog.InitializePrinterControls;

When no printer is installed on computer or Spooler service is stopped,
Access violation
error is shown when button Print is clicked in preview. Error is in this
condition:
if (FPrinter = nil) or (FPrinter.PrinterSetup.PrinterNames.Count = 0) then
Right condition is that:
if (FPrinter = nil) or (FPrinter.PrinterSetup.PrinterNames.Count = 0) or
// I have no printer, but I have in printer dialog => without
this I get access violation error
((cbxPrinters.Items.Count = 1) and
(cbxPrinters.Items.IndexOf(cDefault)<>-1)) then

Regards
Roman Krupicka

nicocizik

Hi Roman,

Thanks for the feedback. This was an issue in ReportBuilder 6.x and has
been addressed in RB 7.x by adding the Screen device as a printer when no
printers are installed on a computer. This automatically assigns the
Default printer to the Screen rather than causing an AV.

--

rbuser

Hi,
I have RB 7.04 for Delphi 5. Screen printer doesn't solve this error.

1. Stop Spooler
2. Show preview on screen - it is OK.
3. Click on Print button - you can see AV....

Regards
Roman Krupicka

nicocizik

Hi Roman,

In my testing with RB 7.04 and Delphi 5, printing from the preview with no
printers installed on my computer throws an exception claiming that it is
not possible to print using the screen device. This is purely an
informative message and is not an AV error. If you take a look in the
ppPrintr.pas file at the TppPrinterList.GetSystemDefaultPrinterName
function, you will see that when there are no printers installed on your
machine, the default is set to Screen.

--

rbuser

Hi Nico,
it is very strange... I tried to make pure new application with TppReport
component only.
I didn't change any settings, I put TppLabel on Detail band only.
I stopped spooler, run app and clicked on button -> ppReport1.Print. OK -
preview was
shown without any problems, but after clicking on Print button in left upper
corner,
I got AV fault...

Win2000 SP4, RB 7.04, Delphi 5 Update pack 1

Regards
Roman

**********************************************************
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, ppPrnabl, ppClass, ppCtrls, ppBands, ppCache, ppComm, ppRelatv,
ppProd, ppReport;

type
TForm1 = class(TForm)
ppReport1: TppReport;
ppHeaderBand1: TppHeaderBand;
ppDetailBand1: TppDetailBand;
ppFooterBand1: TppFooterBand;
ppLabel1: TppLabel;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
begin
ppReport1.Print;
end;

end.

**********************************************************

nicocizik

Hi Roman,

What does the AV message say? Are you able to trace into the RB code after
the AV error occurs? Try setting your Delphi IDE to stop on exceptions and
see if you can do so.

--
Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com

rbuser

Hi Nico,
message is: AV at address 04AD115 in module 'Project1.exe'. Read of address
0000001D.
Problem is in unit ppPDlg in procedure InitializePrinterControls. Look at
rows with ******.

Regards
Roman

procedure TppPrintDialog.InitializePrinterControls;
var
liIndex: Integer;
begin

cbxPrinters.Items.Assign(FPrinter.PrinterSetup.PrinterNames);

{remove 'screen' from printer names option}
liIndex := cbxPrinters.Items.IndexOf(cScreen);
cbxPrinters.Items.Delete(liIndex);

if (FPrinter = nil) or (FPrinter.PrinterSetup.PrinterNames.Count = 0)
***************************************************
// >>> this condition is necessary for avoid to AV <<<
// or ((cbxPrinters.Items.Count = 1) and
(cbxPrinters.Items.IndexOf(cDefault)<>-1))
***************************************************
then
begin
cbxPrinters.Visible := False;
btnPrinterProperties.Visible := False;
lblNoPrintersInstalled.Visible := True;

{display caption, 'There are no printers currently connected to your
computer'}
lblNoPrintersInstalled.Caption := ppLoadStr(8);
end
else
begin
for liIndex := 0 to cbxPrinters.Items.Count - 1 do
begin
******************************************************
// >>> AV is shown on this condition <<<
if (ppPrinters.PrinterInfo[cbxPrinters.Items[liIndex]].IsLocal)
then
******************************************************
cbxPrinters.Items.Objects[liIndex] := TObject(0)
else
cbxPrinters.Items.Objects[liIndex] := TObject(1);
end;
cbxPrinters.Sorted := True;
cbxPrinters.ItemIndex :=
cbxPrinters.Items.IndexOf(FPrinter.PrinterSetup.PrinterName);
if cbxPrinters.ItemIndex = -1 then
begin
FPrinter.PrinterSetup.PrinterName := cbxPrinters.Items[0];
cbxPrinters.ItemIndex := 0;
end;
end;
UpdatePrinterSettings;
end; {procedure, InitializePrinterControls}

nicocizik

Hi Roman,

I am still unable to recreate this error. I have traced through the code
you mentioned and everything seemed to work correctly. Is there something
else I'm missing here? When you say that you stop the spooler, are you
pausing the print job from the Windows Printer dialog? What is the purpose
of this?

--
Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com

rbuser

Hi Nico,
stop spooler = stop Spooler service (net stop Spooler /Y).
I try to emulate PC without printers. I want to print to file
without any printer, but I get AV fault.

I use TExtraDevices for Delphi, version 2.8.

**********************************************
I tried to debug that code and here are my findings:
**********************************************
if (FPrinter = nil) or (FPrinter.PrinterSetup.PrinterNames.Count = 0)
=========================================
FPrinter.FPrinterName = 'Screen'
FPrinter.PrinterSetup.PrinterNames.Count = 2 ([0] = 'Default', [1] =
'Screen')
**********************************************
else
begin
for liIndex := 0 to cbxPrinters.Items.Count - 1 do
begin
if (ppPrinters.PrinterInfo[cbxPrinters.Items[liIndex]].IsLocal)
then
cbxPrinters.Items.Objects[liIndex] := TObject(0)
else
cbxPrinters.Items.Objects[liIndex] := TObject(1);
end;

=========================================
ppPrinters.PrinterInfo['Default'] = nil !!!!! AV Fault !!!!!

ppPrinters.PrinterInfo['Screen'] <> nil
-> it is OK, but at start of InitializePrinterControls procedure is this
code:

{remove 'screen' from printer names option}
liIndex := cbxPrinters.Items.IndexOf(cScreen);
cbxPrinters.Items.Delete(liIndex);
**********************************************

Regards
Roman

nicocizik

Hi Roman,


What is the purpose of doing this? Are you trying to export to a different
format using TExtraDevices? Are you trying to print to a PRN file? I am
unclear why or how you would like to print a report without a printer
installed. Your debug information makes sense but I still am unable to
recreate the AV. Where are you setting the default device to nil?

--
Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com

rbuser

Hi Nico,
some of our customers haven't installed any printer on their computer.
I know it is strange:-), but they exist. And they want to print to file
(for example PDF) and send result by e-mail. I try to emulate their system.
We use TExtraDevices for printing to file.
I set the default device to nil nowhere. In my simple app, I put component
on the form only, put one TppLabel on detail band and print. It's all.

Regards
Roman

nicocizik

Hi Roman,

If you are printing to file, the device selected in the printer drop down
should not matter. Once you select the Print to File option on the Print
Dialog, this becomes irrelevant. Are your customers getting an AV when they
try to print to file with no printer installed? Be sure you have the
AllowPrintToFile property set to True on the report. This will give you the
extra print to file options in the print dialog and then allow your
customers to print to an exported file type.

--
Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com