c# - 在 C# 中打印到 LPT1

Question

如何使用文件 LPT1. 在 C# 中直接打印到点阵打印机。

我用 fopen 在 C++ 上完成了它，但我不知道如何在 c# 中完成它。

非常感谢您

Answer 1

在 Windows 中将打印机设置为 Generic/Text Only，然后打印到它。

这是我用来打印到具有自己编码文本格式的标签打印机的代码。

using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Drawing.Printing;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.IO;

namespace whatever {

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?
        dwCount = szString.Length;
        // 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.
        bool success = SendBytesToPrinter(szPrinterName, pBytes, dwCount);
        Marshal.FreeCoTaskMem(pBytes);
        return success;
    }
}
}

然后从另一个类中调用它，如下所示：

    private bool PrintLabels(string printerName)
    {
        return RawPrinterHelper.SendStringToPrinter(printerName, this.Text);
    }

（编辑：如果有人看到任何与非托管资源相关的主要 fubars，请在评论中告诉我）

Answer 2

也许您不能打印到设备“LPT1”，而是打印到您必须首先安装的“哑电传打印机”。如果它们存在于现代 Windows 中......所以你应该打印到“mydumbprinter”，它又使用 LPT1 作为打印机端口。当我按照上面 Cocowalla 的 Source 链接进行操作时，在我看来，您可以在 PrinterDialog 中选择一台打印机。生成的打印机名称更可能是“Laserjet”而不是“LPT1”。

Answer 3

在 C# 中，首先您需要使用该CreateFile方法连接到该端口，然后打开一个文件流到该端口以最终写入它。这是一个示例类，它将两行写入LPT1.

using Microsoft.Win32.SafeHandles;
using System;
using System.IO;
using System.Runtime.InteropServices;

namespace YourNamespace
{
public static class Print2LPT
        {
            [DllImport("kernel32.dll", SetLastError = true)]
            static extern SafeFileHandle CreateFile(string lpFileName, FileAccess dwDesiredAccess,uint dwShareMode, IntPtr lpSecurityAttributes, FileMode dwCreationDisposition, uint dwFlagsAndAttributes, IntPtr hTemplateFile);

            public static bool Print()
            {
                string nl = Convert.ToChar(13).ToString() + Convert.ToChar(10).ToString();
                bool IsConnected= false;

                string sampleText ="Hello World!" + nl +
                "Enjoy Printing...";     
                try
                {
                    Byte[] buffer = new byte[sampleText.Length];
                    buffer = System.Text.Encoding.ASCII.GetBytes(sampleText);

                    SafeFileHandle fh = CreateFile("LPT1:", FileAccess.Write, 0, IntPtr.Zero, FileMode.OpenOrCreate, 0, IntPtr.Zero);
                    if (!fh.IsInvalid)
                    {
                        IsConnected= true;                    
                        FileStream lpt1 = new FileStream(fh,FileAccess.ReadWrite);
                        lpt1.Write(buffer, 0, buffer.Length);
                        lpt1.Close();
                    }

                }
                catch (Exception ex)
                {
                    string message = ex.Message;
                }

                return IsConnected;
            }
        }
}

假设您的打印机连接在LPT1端口上，如果没有，您将需要调整CreateFile方法以匹配您正在使用的端口。

您可以使用以下行在程序中的任何位置调用该方法

Print2LPT.Print();

我认为这是解决您的问题的最短和最有效的解决方案。