Xps printing from windows service

I'm trying to print XPS documents from a windows service on the .net framework. Since Microsoft does not support printing by using System.Drawing.Printing nor by using System.Printing (WPF), I'm using the native XPSPrint API.
This is suggested to me by Aspose in http://www.aspose.com/documentation/.net-components/aspose.words-for-.net/howto-print-a-document-on-a-server-via-the-xpsprint-api.html.

When I try to print an XPS document from a windows service, the result contains strange characters instead of the text I want.

I tried with different printers (including virtual printers like for instance PDFCreator), different users and user-privileges for the service, different xps generators (aspose, word 2007, word 2010), different platforms (windows 7, windows 2008 R2) but all have the same result.

Does anybody knows how to solve this? Any help would be appreciated!

For those who want to try it, I shared some files via:

https://docs.google.com/leaf?id=0B4J93Ly5WzQKNWU2ZjM0MDYtMjFiMi00NzM0LTg4MTgtYjVlNDA5NWQyMTc3&hl=nl

• document.xps: the XPS document to print
• document_printed_to_pdfcreator.pdf: the printed document that demonstrates what is going wrong
• XpsPrintTest.zip: a sample VS2010 solution with the sample code

The sample code for the managed windows service is:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Linq;
using System.ServiceProcess;
using System.Text;
using System.IO;
using System.Threading;
using System.Runtime.InteropServices;

namespace PrintXpsService
{
public partial class XpsPrintService : ServiceBase
{
    // Change name of printer here
    private String f_printerName = "PDFCreator";

    // path to some file where logging is done
    private String f_logFile = @"C:\temp\testdoc\xps_printing_service_log.txt";

    // path to xps file to print
    private String f_xpsFile = @"C:\temp\testdoc\document.xps";

    public XpsPrintService()
    {
        InitializeComponent();
    }

    private void Log(String fmt, params Object[] args)
    {
        try
        {
            DateTime now = DateTime.Now;

            using (StreamWriter wrt = new StreamWriter(f_logFile, true))
            {
                wrt.Write("{0} {1} - ", now.ToShortDateString(), now.ToShortTimeString());
                wrt.WriteLine(fmt, args);
            }
        }
        catch (Exception ex)
        {
        }
    }

    protected override void OnStart(string[] args)
    {
        // uncomment to allow to connect debugger
        //int i = 0;
        //while (i == 0)
        //{
        //    if (i == 0)
        //    {
        //        Thread.Sleep(1000);
        //    }
        //}

        Log("Starting Service");
        try
        {
            Log("Printing xps file {0}", f_xpsFile);

            using (Stream stream = new FileStream(f_xpsFile, FileMode.Open, FileAccess.Read))
            {
                Log("Starting to print on printer {0}", f_printerName);
                String jobName = f_xpsFile;
                this.Print(stream, jobName);
            }
            Log("Document printed");
        }
        catch (Exception ex)
        {
            Log("Exception during execution: {0}", ex.Message);
            Log("  {0}", ex.StackTrace);
            Exception inner = ex.InnerException;
            while (inner != null)
            {
                Log("=== Inner Exception: {0}", inner.Message);
                Log("    {0}", inner.StackTrace);
                inner = inner.InnerException;
            }
        }
    }

    protected override void OnStop()
    {
    }

    public void Print(Stream stream, String jobName)
    {
        String printerName = f_printerName;
        IntPtr completionEvent = CreateEvent(IntPtr.Zero, true, false, null);
        try
        {
            IXpsPrintJob job;
            IXpsPrintJobStream jobStream;

            StartJob(printerName, jobName, completionEvent, out job, out jobStream);
            CopyJob(stream, job, jobStream);
            WaitForJob(completionEvent, -1);
            CheckJobStatus(job);
        }
        finally
        {
            if (completionEvent != IntPtr.Zero)
                CloseHandle(completionEvent);
        }
    }

    private void StartJob(String printerName,
        String jobName, IntPtr completionEvent,
        out IXpsPrintJob job,
        out IXpsPrintJobStream jobStream)
    {
        int result = StartXpsPrintJob(printerName, jobName, null, IntPtr.Zero, completionEvent,
            null, 0, out job, out jobStream, IntPtr.Zero);
        if (result != 0)
            throw new Win32Exception(result);
    }


    private void CopyJob(Stream stream, IXpsPrintJob job, IXpsPrintJobStream jobStream)
    {
        try
        {
            byte[] buff = new byte[4096];
            while (true)
            {
                uint read = (uint)stream.Read(buff, 0, buff.Length);
                if (read == 0)
                    break;
                uint written;
                jobStream.Write(buff, read, out written);

                if (read != written)
                    throw new Exception("Failed to copy data to the print job stream.");
            }

            // Indicate that the entire document has been copied.
            jobStream.Close();
        }
        catch (Exception)
        {
            // Cancel the job if we had any trouble submitting it.
            job.Cancel();
            throw;
        }
    }

    private void WaitForJob(IntPtr completionEvent, int timeout)
    {
        if (timeout < 0)
            timeout = -1;

        switch (WaitForSingleObject(completionEvent, timeout))
        {
            case WAIT_RESULT.WAIT_OBJECT_0:
                // Expected result, do nothing.
                break;

            case WAIT_RESULT.WAIT_TIMEOUT:
                // timeout expired
                throw new Exception("Timeout expired");

            case WAIT_RESULT.WAIT_FAILED:
                throw new Exception("Wait for the job to complete failed");

            default:
                throw new Exception("Unexpected result when waiting for the print job.");
        }
    }

    private void CheckJobStatus(IXpsPrintJob job)
    {
        XPS_JOB_STATUS jobStatus;
        job.GetJobStatus(out jobStatus);
        switch (jobStatus.completion)
        {
            case XPS_JOB_COMPLETION.XPS_JOB_COMPLETED:
                // Expected result, do nothing.
                break;
            case XPS_JOB_COMPLETION.XPS_JOB_IN_PROGRESS:
                // expected, do nothing, can occur when printer is paused
                break;
            case XPS_JOB_COMPLETION.XPS_JOB_FAILED:
                throw new Win32Exception(jobStatus.jobStatus);
            default:
                throw new Exception("Unexpected print job status.");
        }
    }

    [DllImport("XpsPrint.dll", EntryPoint = "StartXpsPrintJob")]
    private static extern int StartXpsPrintJob(
        [MarshalAs(UnmanagedType.LPWStr)] String printerName,
        [MarshalAs(UnmanagedType.LPWStr)] String jobName,
        [MarshalAs(UnmanagedType.LPWStr)] String outputFileName,
        IntPtr progressEvent,   // HANDLE
        IntPtr completionEvent, // HANDLE
        [MarshalAs(UnmanagedType.LPArray)] byte[] printablePagesOn,
        UInt32 printablePagesOnCount,
        out IXpsPrintJob xpsPrintJob,
        out IXpsPrintJobStream documentStream,
        IntPtr printTicketStream);  // This is actually "out IXpsPrintJobStream", but we don't use it and just want to pass null, hence IntPtr.

    [DllImport("Kernel32.dll", SetLastError = true)]
    private static extern IntPtr CreateEvent(IntPtr lpEventAttributes, bool bManualReset, bool bInitialState, string lpName);

    [DllImport("Kernel32.dll", SetLastError = true, ExactSpelling = true)]
    private static extern WAIT_RESULT WaitForSingleObject(IntPtr handle, Int32 milliseconds);

    [DllImport("Kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool CloseHandle(IntPtr hObject);
}

/// <summary>
/// This interface definition is HACKED.
/// 
/// It appears that the IID for IXpsPrintJobStream specified in XpsPrint.h as 
/// MIDL_INTERFACE("7a77dc5f-45d6-4dff-9307-d8cb846347ca") is not correct and the RCW cannot return it.
/// But the returned object returns the parent ISequentialStream inteface successfully.
/// 
/// So the hack is that we obtain the ISequentialStream interface but work with it as 
/// with the IXpsPrintJobStream interface. 
/// </summary>
[Guid("0C733A30-2A1C-11CE-ADE5-00AA0044773D")]  // This is IID of ISequenatialSteam.
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
interface IXpsPrintJobStream
{
    // ISequentualStream methods.
    void Read([MarshalAs(UnmanagedType.LPArray)] byte[] pv, uint cb, out uint pcbRead);
    void Write([MarshalAs(UnmanagedType.LPArray)] byte[] pv, uint cb, out uint pcbWritten);
    // IXpsPrintJobStream methods.
    void Close();
}

[Guid("5ab89b06-8194-425f-ab3b-d7a96e350161")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
interface IXpsPrintJob
{
    void Cancel();
    void GetJobStatus(out XPS_JOB_STATUS jobStatus);
}

[StructLayout(LayoutKind.Sequential)]
struct XPS_JOB_STATUS
{
    public UInt32 jobId;
    public Int32 currentDocument;
    public Int32 currentPage;
    public Int32 currentPageTotal;
    public XPS_JOB_COMPLETION completion;
    public Int32 jobStatus; // UInt32
};

enum XPS_JOB_COMPLETION
{
    XPS_JOB_IN_PROGRESS = 0,
    XPS_JOB_COMPLETED = 1,
    XPS_JOB_CANCELLED = 2,
    XPS_JOB_FAILED = 3
}

enum WAIT_RESULT
{
    WAIT_OBJECT_0 = 0,
    WAIT_ABANDONED = 0x80,
    WAIT_TIMEOUT = 0x102,
    WAIT_FAILED = -1 // 0xFFFFFFFF
}
}

Note: some links for more information:

• MS not supporting printing from managed code: http://support.microsoft.com/kb/324565 , http://msdn.microsoft.com/en-us/library/system.drawing.printing.aspx and http://msdn.microsoft.com/en-us/library/bb613549.aspx

• XPSPrint API: http://msdn.microsoft.com/en-us/library/dd374565(VS.85).aspx