printing with winspool windows api using c#

Question

Hi,
I am trying to develop a simple application to print different kind of documents.
I am using winspool api. My problem is, document is added in printer queue and its showing status printing. but its not printing. WritePrinter function returning true but its not printing. i am stuck in this.
any help will appreciated, anyone has idea to find errors and correct my code.

beside this i can use other way also (but don't want to use Process or ProcessInfo class). I want to print silently from my application.

my code is below

 

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public class DOCINFOA
{
[MarshalAs(UnmanagedType.LPStr)]
public string pDocName;
[MarshalAs(UnmanagedType.LPStr)]
public string pOutputFile;
[MarshalAs(UnmanagedType.LPStr)]
public string pDataType;
}
[DllImport(winspool.drv, CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern Boolean SetDefaultPrinter(String name);
[DllImport(winspool.Drv, EntryPoint = OpenPrinterA, SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool OpenPrinter([MarshalAs(UnmanagedType.LPStr)] string szPrinter, out IntPtr hPrinter, IntPtr pd);
[DllImport(winspool.Drv, EntryPoint = ClosePrinter, SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool ClosePrinter(IntPtr hPrinter);
[DllImport(winspool.Drv, EntryPoint = StartDocPrinterA, SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool StartDocPrinter(IntPtr hPrinter, Int32 level, [In, MarshalAs(UnmanagedType.LPStruct)] DOCINFOA di);
[DllImport(winspool.Drv, EntryPoint = EndDocPrinter, SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool EndDocPrinter(IntPtr hPrinter);
[DllImport(winspool.Drv, EntryPoint = StartPagePrinter, SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool StartPagePrinter(IntPtr hPrinter);
[DllImport(winspool.Drv, EntryPoint = EndPagePrinter, SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool EndPagePrinter(IntPtr hPrinter);
[DllImport(winspool.Drv, EntryPoint = WritePrinter, SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool WritePrinter(IntPtr hPrinter, IntPtr pBytes, Int32 dwCount, out Int32 dwWritten);

public static bool SendBytesToPrinter(string szPrinterName, IntPtr pBytes, Int32 dwCount)
{
Int32 dwError = 0, dwWritten = 0;
IntPtr hPrinter = new IntPtr(0);
DOCINFOA di = new DOCINFOA();
bool bSuccess = false;

di.pDocName = "Document";
di.pDataType = "RAW";


if (OpenPrinter(szPrinterName.Normalize(), out hPrinter, IntPtr.Zero))
{
if (hPrinter.ToInt32() == 0)
return false; //Printer not found!!

if (StartDocPrinter(hPrinter, 1, di))
{

if (StartPagePrinter(hPrinter))
{

bSuccess = WritePrinter(hPrinter, pBytes, dwCount, out dwWritten);
EndPagePrinter(hPrinter);
}
EndDocPrinter(hPrinter);
}
ClosePrinter(hPrinter);
}

if (bSuccess == false)
{
dwError = Marshal.GetLastWin32Error();
}
return bSuccess;
}
public static bool SendFileToPrinter(string szPrinterName, string szFileName)
{
bool bSuccess = false;
try
{

FileStream fs = new FileStream(szFileName, FileMode.Open);

BinaryReader br = new BinaryReader(fs);

Byte[] bytes = new Byte[fs.Length];


IntPtr pUnmanagedBytes = new IntPtr(0);
int nLength;

nLength = Convert.ToInt32(fs.Length);

bytes = br.ReadBytes(nLength);

pUnmanagedBytes = Marshal.AllocCoTaskMem(nLength);

Marshal.Copy(bytes, 0, pUnmanagedBytes, nLength);

bSuccess = SendBytesToPrinter(szPrinterName, pUnmanagedBytes, nLength);

Marshal.FreeCoTaskMem(pUnmanagedBytes);

br.Close();
fs.Close();
}
catch (Exception ex)
{ string s = ex.Message.ToString(); }
return bSuccess;

}