Question

I’m trying to print a pcl file programatically in c#.

I’m using the following Microsoft link for reference. (Note it’s in VB)

http://support.microsoft.com/kb/298141

Unfortunatly, it’s not work .. I’m only getting blank pages printed.

Note that if I just copy the pcl file to the printer from prompt – i.e. copy filename printer. The page gets printed corrrectly.

Suggestions?

public class PrintRaw
  {
    [StructLayout(LayoutKind.Sequential)]
    public class DocInfo
    {
      [MarshalAs(UnmanagedType.LPWStr)] public String docName;
      [MarshalAs(UnmanagedType.LPWStr)] public String outputFile;
      [MarshalAs(UnmanagedType.LPWStr)] public String dataType;
    }

    [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)] DocInfo 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 void Print(String printerName, String filename)
    {
      IntPtr lhPrinter;
      OpenPrinter(printerName, out lhPrinter, new IntPtr(0));

      if (lhPrinter.ToInt32() == 0)
        return; //Printer not found!!

      var rawPrinter = new DocInfo() {docName = "My Document", dataType = "RAW"};

      StartDocPrinter(lhPrinter, 1, rawPrinter);

      using (var b = new BinaryReader(File.Open(filename, FileMode.Open)))
      {
        var length = (int) b.BaseStream.Length;
        const int bufferSize = 8192;

        var numLoops = length/bufferSize;
        var leftOver = length%bufferSize;


        for (int i = 0; i < numLoops; i++)
        {
          var buffer = new byte[bufferSize];
          int dwWritten;

          b.Read(buffer, 0, bufferSize);
          IntPtr unmanagedPointer = Marshal.AllocHGlobal(buffer.Length);
          Marshal.Copy(buffer, 0, unmanagedPointer, buffer.Length);
          WritePrinter(lhPrinter, unmanagedPointer, bufferSize, out dwWritten);
          Marshal.FreeHGlobal(unmanagedPointer);
        }

        if (leftOver > 0)
        {
          var buffer = new byte[leftOver];
          int dwWritten;

          b.Read(buffer, 0, leftOver);
          IntPtr unmanagedPointer = Marshal.AllocHGlobal(buffer.Length);
          Marshal.Copy(buffer, 0, unmanagedPointer, buffer.Length);
          WritePrinter(lhPrinter, unmanagedPointer, leftOver, out dwWritten);
          Marshal.FreeHGlobal(unmanagedPointer);
        }
      }

      EndDocPrinter(lhPrinter);
      ClosePrinter(lhPrinter);
    }
  }

Answer 1

Ok, it seems like the datatype that I was using was invalid in the example. I updated it to the following (note the setting of Charset) and it fixed the problem.

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public class DOC_INFO_1
{
  [MarshalAs(UnmanagedType.LPStr)]
  public string pDocName;
  [MarshalAs(UnmanagedType.LPStr)]
  public string pOutputFile;
  [MarshalAs(UnmanagedType.LPStr)]
  public string pDataType;
}