How to print using C# and winspool api

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C#

Windows

API

print

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 returning true but its not printing. i am stuck in this.
any help will appreciated, anyone has idea to find errors and any 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.

What I have tried:

[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; // Assume failure unless you specifically succeed.

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

            // Open the printer.
            if (OpenPrinter(szPrinterName.Normalize(), out hPrinter, IntPtr.Zero))
            {
                if (hPrinter.ToInt32() == 0)
                    return false; //Printer not found!!
                // Start a document.
                if (StartDocPrinter(hPrinter, 1, di))
                {
                    // Start a page.
                    if (StartPagePrinter(hPrinter))
                    {
                        // Write your bytes.
                        bSuccess = WritePrinter(hPrinter, pBytes, dwCount, out dwWritten);
                        EndPagePrinter(hPrinter);
                    }
                    EndDocPrinter(hPrinter);
                }
                ClosePrinter(hPrinter);
            }
            // If you did not succeed, GetLastError may give more information
            // about why not.
            if (bSuccess == false)
            {
                dwError = Marshal.GetLastWin32Error();
            }
            return bSuccess;
        }
        public static bool SendFileToPrinter(string szPrinterName, string szFileName)
        {
            bool bSuccess = false;
            try
            {
                // Open the file.
                FileStream fs = new FileStream(szFileName, FileMode.Open);
                // Create a BinaryReader on the file.
                BinaryReader br = new BinaryReader(fs);
                // Dim an array of bytes big enough to hold the file's contents.
                Byte[] bytes = new Byte[fs.Length];

                // Your unmanaged pointer.
                IntPtr pUnmanagedBytes = new IntPtr(0);
                int nLength;

                nLength = Convert.ToInt32(fs.Length);
                // Read the contents of the file into the array.
                bytes = br.ReadBytes(nLength);
                // Allocate some unmanaged memory for those bytes.
                pUnmanagedBytes = Marshal.AllocCoTaskMem(nLength);
                // Copy the managed byte array into the unmanaged array.
                Marshal.Copy(bytes, 0, pUnmanagedBytes, nLength);
                // Send the unmanaged bytes to the printer.
                bSuccess = SendBytesToPrinter(szPrinterName, pUnmanagedBytes, nLength);
                //PrintText(szPrinterName, pUnmanagedBytes, nLength);
                // Free the unmanaged memory that you allocated earlier.
                Marshal.FreeCoTaskMem(pUnmanagedBytes);

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

        }