Updating printersettings

Benjamin,

Im not sure what your trying to do with the GlobalLock on the printer handle.... but its not right. The bigger problems are this:

1.) SpaceNeeded is defined as word, and should be DWORD. (this is the second occurrence of the same problem that I have seen in about a week?....)
2.) for DocumentProperties (the second call) you are specifying DM_IN_BUFFER but are passing in an empty structure??? You have basically told the api to use the values in the buffer (some of which are pointers to char strings) and provided the api with junk... resulting in a gpf.

Try the following, which should work correctly for you.  

var  dwSpaceNeeded:       DWORD;
     dwDMSize:            DWORD;
     dmMode:              TDeviceMode;
     lpdmMode:            PDeviceMode;
     lpPrintInfo2:        PPrinterInfo2;
     hPrinter:            THandle;
     PrinterName:         String;
begin

  // For demo only ** REPLACE WITH YOUR CODE **
  PrinterName:=Printer.Printers[Printer.PrinterIndex];

  // Set structure memory to nil
  lpPrintInfo2:=nil;

  // Open the printer
  if (OpenPrinter(PChar(PrinterName), hPrinter, nil)) then
  begin
     // Get required memory size
     GetPrinter(hPrinter, 2, lpPrintInfo2, 0, @dwSpaceNeeded);
     // Allocate memory
     lpPrintInfo2:=AllocMem(dwSpaceNeeded);
     // Resource protection
     try
        // Get printer info
        GetPrinter(hPrinter, 2, lpPrintInfo2, dwSpaceNeeded, @dwSpaceNeeded);
        // Get dev mode size
        dwDMSize:=DocumentProperties(Handle, hPrinter, PChar(PrinterName), dmMode, dmMode, 0);
        // Allocate memory for the device mode
        lpdmMode:=AllocMem(dwDMSize);
        // Resource protection
        try
           DocumentProperties(Handle, hPrinter, PChar(PrinterName), lpdmMode^, lpdmMode^, DM_OUT_BUFFER or DM_IN_PROMPT);
           // Update the printer settings
           ResetDC(hPrinter, lpdmMode^);
        finally
           // Free allocated memory
           FreeMem(lpdmMode);
        end;
     finally
        // Free allocated memory
        FreeMem(lpPrintInfo2);
     end;
     // Close printer handle
     ClosePrinter(hPrinter);
  end;

end;


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Regards,
Russell

Well Russell,

I've tried your code and it compiles and runs, but when I change any printer properties it will not keep the changes. When I for instance change the lay-out of a page to landscape, instead of portrait, it still prints on a portrait lay-out. Some way or another it doesn't keep the changes of the printer properties...

Thankx,

Benjamin

You indicated your problem was with an access violation, and I corrected your code so that it was syntactically and functionally correct. Now if you want this to work, then you should not be using ResetDC(...) which was meant to take an HDC handle, not a printer handle.

What you should be using is SetPrinter, passing the following:

SetPrinter(hPrinter, 2, lpdmMode, 0);

----

Russell

Hi Russell,

yes, my code is now syntactically correct and works almost fine. So thanks for that.
But when I try to apply the settings to change the printer properties it will give a winspool.drv error at SetPrinter(hPrinter, 2, lpdmMode, 0);. I tried the program on a different computer and still it give the winspool.drv error. So something goes wrong here.

Thankx,

Benjamin

Do you mind sharing the error then? (it would make it easier to figure the problem out)

Russell

Okay, the full error:

exception raised class EAccessViolation with message 'Access violation at address 73001AE5 in module 'winspool.drv'. Read of address 39464450. Process stopped.
It occurs when clicking the 'OK' button of the printer document properties dialog.

Benjamin

Hey Russell,

well it worked eventually... So thankx, now I can finally move on to the next problem...

Benjamin