Changing printer settings using C#

Introduction

I was working on one of the migration projects from VB6 to C#. I had a requirement of printing MS Word document for the application, and the user should be given an option to change printer settings for the document that he/she wants to print, so that user can change page source and duplex property of the printer.

When we started converting code to C#, I found that there is no function in MS Word API to change the duplex property of the printer. Word does provide a parameter in WordApplication class’ PrintOut method, but Microsoft suggests not to use as it is OS and language dependent.

What really worrying was the printing library in .NET. I did not find any class which could change the printer setting with out PrintDocument associated with it. I really feel that .NET should have provided class to change printer settings, or for that matter, .NET should have provided a library which helps prevent developers end up using WIN API which is OS dependent (I ended up in designing a class for printer which is OS independent).

The other problem is, the OpenPrinter does not work for network printers (although Microsoft suggests a way of setting up the printer, I can’t do the same with the client). The funny part is that the VB6 code works without any problem (access denied) and all MS Office tools work all right, then why not C# code?

Following is the C# code to change printer settings globally. This is only a sample code. Please excuse me as the code is not elegantly written, the only intention was to explain how it works. The code will not work for network printers. Please refer the following link for more information for setting up network printer.

• MSDN

public class PrinterSettings 
{
#region "Private Variables"
private IntPtr hPrinter = new System.IntPtr() ;
private PRINTER_DEFAULTS PrinterValues = new PRINTER_DEFAULTS();
private PRINTER_INFO_2 pinfo = new PRINTER_INFO_2();
private DEVMODE dm;
private IntPtr ptrDM;
private IntPtr ptrPrinterInfo;
private int sizeOfDevMode = 0;
private int lastError;
private int nBytesNeeded;
private long nRet; 
private int intError;
private System.Int32 nJunk;
private IntPtr yDevModeData;

#endregion
#region "Win API Def"
[DllImport("kernel32.dll", EntryPoint="GetLastError", SetLastError=false,
ExactSpelling=true, CallingConvention=CallingConvention.StdCall)]
private static extern Int32 GetLastError();
[DllImport("winspool.Drv", EntryPoint="ClosePrinter", SetLastError=true, 
ExactSpelling=true, CallingConvention=CallingConvention.StdCall)]
private static extern bool ClosePrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint="DocumentPropertiesA", SetLastError=true, 
ExactSpelling=true, CallingConvention=CallingConvention.StdCall)]
private static extern int DocumentProperties (IntPtr hwnd, IntPtr hPrinter, 
[MarshalAs(UnmanagedType.LPStr)] string pDeviceNameg, 
IntPtr pDevModeOutput, ref IntPtr pDevModeInput, int fMode);
[DllImport("winspool.Drv", EntryPoint="GetPrinterA", SetLastError=true, 
    CharSet=CharSet.Ansi, ExactSpelling=true, 
    CallingConvention=CallingConvention.StdCall)]
private static extern bool GetPrinter(IntPtr hPrinter, Int32 dwLevel, 
IntPtr pPrinter, Int32 dwBuf, out Int32 dwNeeded);
/*[DllImport("winspool.Drv", EntryPoint="OpenPrinterA", 
    SetLastError=true, CharSet=CharSet.Ansi, 
    ExactSpelling=true, CallingConvention=CallingConvention.StdCall)]
static extern bool OpenPrinter([MarshalAs(UnmanagedType.LPStr)] string szPrinter, 
out IntPtr hPrinter, ref PRINTER_DEFAULTS pd)

[ DllImport( "winspool.drv",CharSet=CharSet.Unicode,ExactSpelling=false,
CallingConvention=CallingConvention.StdCall )]
public static extern long OpenPrinter(string pPrinterName, 
         ref IntPtr phPrinter, int pDefault);*/

/*[DllImport("winspool.Drv", EntryPoint="OpenPrinterA", 
    SetLastError=true, CharSet=CharSet.Ansi, 
    ExactSpelling=true, CallingConvention=CallingConvention.StdCall)]
static extern bool OpenPrinter([MarshalAs(UnmanagedType.LPStr)] string szPrinter, 
out IntPtr hPrinter, ref PRINTER_DEFAULTS pd);
*/ 
[DllImport("winspool.Drv", EntryPoint="OpenPrinterA", 
    SetLastError=true, CharSet=CharSet.Ansi, 
    ExactSpelling=true, CallingConvention=CallingConvention.StdCall)]
private static extern bool 
    OpenPrinter([MarshalAs(UnmanagedType.LPStr)] string szPrinter, 
    out IntPtr hPrinter, ref PRINTER_DEFAULTS pd);
[DllImport("winspool.drv", CharSet=CharSet.Ansi, SetLastError=true)]
private static extern bool SetPrinter(IntPtr hPrinter, int Level, IntPtr 
pPrinter, int Command);

/*[DllImport("winspool.drv", CharSet=CharSet.Ansi, SetLastError=true)]
private static extern bool SetPrinter(IntPtr hPrinter, int Level, IntPtr 
pPrinter, int Command);*/

// Wrapper for Win32 message formatter.
/*[DllImport("kernel32.dll", CharSet=System.Runtime.InteropServices.CharSet.Auto)]
private unsafe static extern int FormatMessage( int dwFlags,
ref IntPtr pMessageSource,
int dwMessageID,
int dwLanguageID,
ref string lpBuffer,
int nSize,
IntPtr* pArguments);*/
#endregion
#region "Data structure"
[StructLayout(LayoutKind.Sequential)]
public struct PRINTER_DEFAULTS
{
public int pDatatype;
public int pDevMode;
public int DesiredAccess;
}
/*[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto)]
public struct PRINTER_DEFAULTS
{
public int pDataType;
public IntPtr pDevMode;
public ACCESS_MASK DesiredAccess;
}*/

[StructLayout(LayoutKind.Sequential)]
private struct PRINTER_INFO_2
{
[MarshalAs(UnmanagedType.LPStr)] public string pServerName; 
[MarshalAs(UnmanagedType.LPStr)] public string pPrinterName; 
[MarshalAs(UnmanagedType.LPStr)] public string pShareName; 
[MarshalAs(UnmanagedType.LPStr)] public string pPortName; 
[MarshalAs(UnmanagedType.LPStr)] public string pDriverName; 
[MarshalAs(UnmanagedType.LPStr)] public string pComment; 
[MarshalAs(UnmanagedType.LPStr)] public string pLocation; 
public IntPtr pDevMode; 
[MarshalAs(UnmanagedType.LPStr)] public string pSepFile; 
[MarshalAs(UnmanagedType.LPStr)] public string pPrintProcessor; 
[MarshalAs(UnmanagedType.LPStr)] public string pDatatype; 
[MarshalAs(UnmanagedType.LPStr)] public string pParameters; 
public IntPtr pSecurityDescriptor; 
public Int32 Attributes; 
public Int32 Priority; 
public Int32 DefaultPriority; 
public Int32 StartTime; 
public Int32 UntilTime; 
public Int32 Status; 
public Int32 cJobs; 
public Int32 AveragePPM; 
}
private const short CCDEVICENAME = 32;
private const short CCFORMNAME = 32;
[StructLayout(LayoutKind.Sequential)] 
public struct DEVMODE 
{ 
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCDEVICENAME)] 
public string dmDeviceName;
public short dmSpecVersion;
public short dmDriverVersion;
public short dmSize;
public short dmDriverExtra;
public int dmFields;
public short dmOrientation;
public short dmPaperSize;
public short dmPaperLength;
public short dmPaperWidth;
public short dmScale;
public short dmCopies;
public short dmDefaultSource;
public short dmPrintQuality;
public short dmColor;
public short dmDuplex;
public short dmYResolution;
public short dmTTOption;
public short dmCollate;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCFORMNAME)] 
public string dmFormName; 
public short dmUnusedPadding;
public short dmBitsPerPel;
public int dmPelsWidth;
public int dmPelsHeight;
public int dmDisplayFlags;
public int dmDisplayFrequency;
}
#endregion
#region "Constants"
private const int DM_DUPLEX = 0x1000;
private const int DM_IN_BUFFER = 8;
private const int DM_OUT_BUFFER = 2;
private const int PRINTER_ACCESS_ADMINISTER = 0x4;
private const int PRINTER_ACCESS_USE = 0x8;
private const int STANDARD_RIGHTS_REQUIRED = 0xF0000;
private const int PRINTER_ALL_ACCESS = 
    (STANDARD_RIGHTS_REQUIRED | PRINTER_ACCESS_ADMINISTER 
    | PRINTER_ACCESS_USE);
#endregion
#region "Function to change printer settings" 
public bool ChangePrinterSetting(string PrinterName,PrinterData PS)

{

if (((int)PS.Duplex < 1) || ((int)PS.Duplex > 3) )
{
throw new ArgumentOutOfRangeException("nDuplexSetting",
                         "nDuplexSetting is incorrect.");
}
else
{
dm = this.GetPrinterSettings( PrinterName);
dm.dmDefaultSource =(short)PS.source; 
dm.dmOrientation = (short)PS.Orientation; 
dm.dmPaperSize =(short)PS.Size;
dm.dmDuplex = (short)PS.Duplex; 
Marshal.StructureToPtr( dm,yDevModeData,true); 
pinfo.pDevMode = yDevModeData;
pinfo.pSecurityDescriptor = IntPtr.Zero;
/*update driver dependent part of the DEVMODE
1 = DocumentProperties(IntPtr.Zero, hPrinter, sPrinterName, yDevModeData
, ref pinfo.pDevMode, (DM_IN_BUFFER | DM_OUT_BUFFER));*/
Marshal.StructureToPtr(pinfo,ptrPrinterInfo,true); 
lastError = Marshal.GetLastWin32Error();
nRet = Convert.ToInt16(SetPrinter(hPrinter, 2, ptrPrinterInfo, 0));
if (nRet == 0)
{
//Unable to set shared printer settings.
lastError = Marshal.GetLastWin32Error();
//string myErrMsg = GetErrorMessage(lastError);
throw new Win32Exception(Marshal.GetLastWin32Error()); 

}
if (hPrinter != IntPtr.Zero) 
ClosePrinter(hPrinter);
return Convert.ToBoolean(nRet);
}
}
private DEVMODE GetPrinterSettings(string PrinterName)
{
PrinterData PData = new PrinterData(); 
DEVMODE dm;
const int PRINTER_ACCESS_ADMINISTER = 0x4;
const int PRINTER_ACCESS_USE = 0x8;
const int PRINTER_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED | 
           PRINTER_ACCESS_ADMINISTER | PRINTER_ACCESS_USE);


PrinterValues.pDatatype =0;
PrinterValues.pDevMode = 0 ;
PrinterValues.DesiredAccess = PRINTER_ALL_ACCESS;
nRet = Convert.ToInt32(OpenPrinter(PrinterName, 
               out hPrinter, ref PrinterValues));
if (nRet == 0)
{
lastError = Marshal.GetLastWin32Error();
throw new Win32Exception(Marshal.GetLastWin32Error()); 
}
GetPrinter(hPrinter, 2, IntPtr.Zero, 0, out nBytesNeeded);
if (nBytesNeeded <= 0)
{
throw new System.Exception("Unable to allocate memory");
}
else
{
// Allocate enough space for PRINTER_INFO_2... 
{ptrPrinterIn fo = Marshal.AllocCoTaskMem(nBytesNeeded)};
ptrPrinterInfo = Marshal.AllocHGlobal(nBytesNeeded);
// The second GetPrinter fills in all the current settings, so all you 
// need to do is modify what you're interested in...
nRet = Convert.ToInt32(GetPrinter(hPrinter, 2, 
    ptrPrinterInfo, nBytesNeeded, out nJunk));
if (nRet == 0)
{
lastError = Marshal.GetLastWin32Error();
throw new Win32Exception(Marshal.GetLastWin32Error()); 
}
pinfo = (PRINTER_INFO_2)Marshal.PtrToStructure(ptrPrinterInfo, 
                                      typeof(PRINTER_INFO_2));
IntPtr Temp = new IntPtr();
if (pinfo.pDevMode == IntPtr.Zero)
{
// If GetPrinter didn't fill in the DEVMODE, try to get it by calling
// DocumentProperties...
IntPtr ptrZero = IntPtr.Zero;
//get the size of the devmode structure
sizeOfDevMode = DocumentProperties(IntPtr.Zero, hPrinter, 
                   PrinterName, ptrZero, ref ptrZero, 0);

ptrDM = Marshal.AllocCoTaskMem(sizeOfDevMode);
int i ;
i = DocumentProperties(IntPtr.Zero, hPrinter, PrinterName, ptrDM, 
ref ptrZero, DM_OUT_BUFFER);
if ((i < 0) || (ptrDM == IntPtr.Zero))
{
//Cannot get the DEVMODE structure.
throw new System.Exception("Cannot get DEVMODE data"); 
}
pinfo.pDevMode = ptrDM;
}
intError = DocumentProperties(IntPtr.Zero, hPrinter, 
          PrinterName, IntPtr.Zero , ref Temp , 0);
//IntPtr yDevModeData = Marshal.AllocCoTaskMem(i1);
yDevModeData= Marshal.AllocHGlobal(intError);
intError = DocumentProperties(IntPtr.Zero, hPrinter, 
         PrinterName, yDevModeData , ref Temp , 2);
dm = (DEVMODE)Marshal.PtrToStructure(yDevModeData, typeof(DEVMODE));
//nRet = DocumentProperties(IntPtr.Zero, hPrinter, sPrinterName, yDevModeData
// , ref yDevModeData, (DM_IN_BUFFER | DM_OUT_BUFFER));
if ((nRet == 0) || (hPrinter == IntPtr.Zero))
{
lastError = Marshal.GetLastWin32Error();
//string myErrMsg = GetErrorMessage(lastError);
throw new Win32Exception(Marshal.GetLastWin32Error()); 
}
return dm;
}
#endregion
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