如何在C＃中通过USB使用Zebra RW 420热敏打印机使用命令打印QR码

在你继续将我的问题标记为重复之前，请相信我，不是 . 我已经完成了这里提供的几乎所有解决方案，但仍然无法让我的应用程序正常工作，所以请你好好花一些时间来帮助我 .

场景：我有一台Zebra RW 420热敏打印机，我想用它来打印带有QR码的代金券 . 我正在使用C＃并且已经按照Scott Chamberlain here和code here给出的所有帮助将命令发送到打印机 . 我有EPL2手册以及CPCL和ZPL参考手册，其中包含很多关于如何格式化命令的内容 .

问题：我发送的所有命令都是打印为命令的纯文本副本，或者打印机只是挂起，其显示屏上显示小信息图标 . 我尝试使用Zebra Utilitis发送相同的命令，但仍然得到与我的示例应用程序相同的结果 . 下面是我的代码片段，请告诉我是否有任何参考库我可能需要它才能使其工作 .

private void btnPrint_Click(object sender, RoutedEventArgs e)
    {
        string s = "! 0 200 200 500 1\nB QR 10 100 M 2 U 10\nMA,QR code ABC123\nENDQR\nFORM\nPRINT";

//还尝试了\ r \ n用于具有相同结果的换行符 .

// Allow the user to select a printer.
        PrintDialog pd = new PrintDialog();

        if ((bool)pd.ShowDialog())
        {
            var bytes = Encoding.ASCII.GetBytes(s);
            // Send a printer-specific to the printer.
            RawPrinterHelper.SendBytesToPrinter(pd.PrintQueue.FullName, bytes, bytes.Length);
        }
    }

由Scott here修改的PrinterHelper类

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, byte[] 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, byte[] 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 = "Zebra Label";
        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();
            throw new Win32Exception(dwError);
        }
        return bSuccess;
    }

}