Set default printer while report generates

rbuser

Setup:
I am programming on Delphi 2010 and Report builder 14. The application is
targeting a laptop running windows 7 that needs to be connected to a docking
station in order to print.

The project:
I am doing some printer checking prior (Find the default printer for that
document and check/wait until that printer is online) to sending the
document to the printer.
I am having some unexpected results.

Approach 1:
Procedure ppReport1PrintDialogCreate(Sender: TObject)
begin
SetDefaultPrinter; //set the default printer on windows.
ppReportShiftLog.Printer := 'Some printer'

while not PrinterIsOnline do
begin
sleep(100);
Application.ProcessMessages;
if fw.bCancelPrinting then //pop cancel form
begin
. Close report
end;
end;
End;

The print dialog selects the first printer not the default.
I am guessing that my timing is off. The print dialog has been created
before I set the default printer.


Approach 2:
Procedure ppReport1PreviewFormCreate
Begin
// Change the on click event and handle the printing myself
TppPrintPreview(ppReportShiftLog.PreviewForm).PrintButton.OnClick :=
OnReportPrintButtonClick;
End

Procedure OnReportPrintButtonClick(Sender: TObject);
Begin
SetDefaultPrinter; //set the default printer on windows.
ppReport1.Printer := 'Some printer'

while not PrinterIsOnline do
begin
sleep(100);
Application.ProcessMessages;
if fw.bCancelPrinting then //pop cancel form
begin
. Close report
end;
end;

//sent the report to the printer
ppReport1.DeviceType := 'Printer';
ppReport1.Print;
end

Here the print dialog displays the correct printer but the document sent to
the printer seems to be incomplete. Most of the time the printer window
displays the document with pages = 'N/A' and nothing would print. I am
guessing that the report has not yet finished generating. I have also tried
to wait until the footer band has been printer by the preview but I get a
similar result. I am also suspect the problem may be due to the
OnReportPrintButtonClick being called by a different Thread.


Please help
Thanks

Temoc Navarro

rbuser

Is it possible to access and change the printer of the report Print Dialog
on procedure ppReport1PrintDialogCreate ?


Temoc Navarro

nicocizik

Hi Temoc,

From your description, it sounds like this is a timing issue more than
anything else. It seems perhaps that the default printer has not been
fully realized by Windows or your app before you are trying to print the
report. My suggestion would be to use an earlier event perhaps when the
application is loaded or to create a timer to allow enough time for the
default printer to be assigned before printing.

rbuser

Thanks for your help but I still unable to accomplish my goal. I hope you
can give me other options.

I do have a timer that starts checking for the printer as soon as the form
is loaded. Once the printer is detected, it is set it as the default
printer. This part works.
The problem occurs when the user clicks the print button before setting the
laptop on the docking station connected to the printer. At this point the
printer has not yet been detected and a waiting window pops waiting for the
printer to be online.
If I force the report to wait (on any other point like on open pipeline, on
print, etc.) for the printer to be online, the user will not be able to
preview the report unless there is a printer.


I created a custom button following the wiki example and I modified it as
follows:

procedure TmyPreview.ehFilebutton_Click(Sender: TObject);
var
fw : TfWaitingWindow;
i : integer;
begin
try
try
//Create the waiting form if the printer is not available yet.
if not CheckForPrinter then
begin
fw := TfWaitingWindow.Create(nil);
fw.Show;
end;
//if we are still looking for a printer wait
while not CheckForPrinter do // CheckForPrinter checks and sets the
printer
begin
sleep(100);
Application.ProcessMessages;
if fw.bCancelPrinting then
begin
exit;
end;
end;
finally
if fw <> nil then
FreeAndNil(fw);
end;
except
on E: Exception do
begin
ShowMessage(E.Message);
end;
end;

//wait another 5 seconds
for I := 0 to 10 do
begin
sleep(500);
Application.ProcessMessages;
end;
// at this point I manually open windows printers and confirm that the
corrected printer is the default
showmessage('Stop, Check default printer on Devices and Printer');

print;
end;

Right away this code gets call prior to the Procedure
ppReport1PreviewFormCreate

Base on the previous code I confirmed that the printer is set prior to
calling the print function. Yet the print Dialog displayed a different
printer.

Is there a wait to try to pass the printer name to the report or the print
dialog inside the ehFilebutton_Click ?

My goal is to stop the print dialog from showing until the printer is
online. Then display the dialog with the correct printer selected. Is there
any other wait where I can accomplish this behavior?

Thanks again.
Temoc Navarro

nicocizik

Hi Temoc,

I would wonder if you could get this to work correctly even if you do so
before the report is previewed. As a test, try executing your "waiting"
code another place in your application (perhaps a temporary button),
then before event previewing the report, plug the laptop into the
docking station, preview the report, then print.

It seems a better solution would be to simply give your users an error
message if they try to print without a valid printer connected.

rbuser

I tested waiting for the printer before calling the preview and it works
fine but it is not acceptable solution.

do you have any idea at what point is the print dialog generated?

is there away to set the ppReport1.Printer inside ehFilebutton_Click ?

Temoc Navarro

nicocizik

Hi Temoc,

Thanks for the info. Since you are able to get this to work before
calling Print, perhaps we can get it working with an earlier event. Try
moving your code to the OnInitializeParameters event of the report and
see if that helps. This is the first event fired once the report is
printed.

rbuser

OnInitializeParameter gets call before the preview is display. I think the
issue is that the print dialog is generated during the preview. thus making
it to late for me to set default printer any time after the preview is
generated.

I think that is best to take a different approach. I will be printing to pdf
instead of the screen and displaying a pdf viewer as the preview with my own
print button. If you see anything wrong with this approach, please let me
know.

Thank you for your help.

Temoc Navarro