Sending data to USB printer in C#?

Question

I have script code for zebra TLP2844 printer in a text file. I need to print that script file to a printer connected via USB. I executed that script using parallel port by using DOS command:

/c type filename.txt >PRN

But the printer is coonnected to USB. How to send printing commands to usb? Should I use the printdocument class?

Answer 1

Microsoft has this sample code available to use:

How to send raw data to a printer by using Visual C# .NET

using System;
using System.Drawing;
using System.Drawing.Printing;
using System.IO;
using System.Runtime.InteropServices;
using System.Windows.Forms;

public class RawPrinterHelper
{
  // Structure and API declarions:
  [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", 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 );

  // SendBytesToPrinter()
  // When the function is given a printer name and an unmanaged array
  // of bytes, the function sends those bytes to the print queue.
  // Returns true on success, false on failure.
  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 = "My C#.NET RAW Document";
    di.pDataType = "RAW";

    // Open the printer.
    if( OpenPrinter( szPrinterName.Normalize(), out hPrinter, IntPtr.Zero ) )
    {
      // 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 )
  {
    // 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];
    bool bSuccess = false;
    // 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);
    // Free the unmanaged memory that you allocated earlier.
    Marshal.FreeCoTaskMem(pUnmanagedBytes);
    return bSuccess;
  }

  public static bool SendStringToPrinter( string szPrinterName, string szString )
  {
    IntPtr pBytes;
    Int32 dwCount;

    // How many characters are in the string?
    // Fix from Nicholas Piasecki:
    // dwCount = szString.Length;
    dwCount = (szString.Length + 1) * Marshal.SystemMaxDBCSCharSize;

    // Assume that the printer is expecting ANSI text, and then convert
    // the string to ANSI text.
    pBytes = Marshal.StringToCoTaskMemAnsi(szString);
    // Send the converted ANSI string to the printer.
    SendBytesToPrinter(szPrinterName, pBytes, dwCount);
    Marshal.FreeCoTaskMem(pBytes);
    return true;
  }
}

Includes bug fix from Nicholas Piasecki