C# ESC/POS 打印越南语

我有一个使用 ESC/POS 将收据打印到收据打印机的应用程序。它需要支持多语言。目前，我已经用汉字（繁体和简体）和泰语进行了测试。他们都工作得很好。

但是，当我尝试打印越南语时，某些字符被“？”替换。

这是我的代码：

public static readonly string ESC = "\u001B";
...
...
...
Encoding enc = Encoding.GetEncoding(1258); //vietnamese code page
string content = "Cơm chiên với các loại gia vị truyền thống làm cho lưỡi của bạn";
string toPrint = ESC + "t" + char.ConvertFromUtf32(94) + "\n" + Encoding.GetEncoding("Latin1").GetString(enc.GetBytes(str));  //code page 94 is for vietnamese (WPC1258). It is get from printer

在打印输出中，一些字符已被替换为“？” （见附图）。任何想法？

UPDATE

根据 Panagiotis Kanavos 的评论，我尝试了以下方法：

Encoding enc = Encoding.GetEncoding(1258); //vietnamese code page
string content = "Cơm chiên với các loại gia vị truyền thống làm cho lưỡi của bạn";
string newStr = Encoding.GetEncoding("Latin1").GetString(enc.GetBytes(content));
string origStr = enc.GetString(Encoding.GetEncoding("Latin1").GetBytes(newStr));

origStr 包含?。我确认在中文和泰文中，origStr将等于content。但NOT对于越南人来说。任何想法？

UPDATE 2

我决定使用 Panagiotis Kanavos 代码，它是bytesToPrint = enc.GetBytes("\x1Bt\x5E\n" + content);，但它给了我完全相同的结果，其中包含?而不是实际的角色。

这就是我将内容（字符串或字节）发送到打印机的方式。

[DllImport("Winspool.drv", EntryPoint = "ClosePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool ClosePrinter(IntPtr hPrinter);

[DllImport("Winspool.drv", EntryPoint = "EndDocPrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool EndDocPrinter(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 = "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 = "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 = "StartPagePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool StartPagePrinter(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 static bool SendBytesToPrinter(string printerName, IntPtr pBytes, int dwCount, string docName = null, string dataType = "RAW")
{
    DOCINFOA di = new DOCINFOA();
    di.pDocName = string.IsNullOrWhiteSpace(docName) ? string.Empty : docName;
    di.pDataType = string.IsNullOrWhiteSpace(dataType) ? "RAW" : dataType;

    IntPtr hPrinter = new IntPtr(0); int dwError = 0, dwWritten = 0; bool bSuccess = false;
    if (OpenPrinter(printerName.Normalize(), out hPrinter, IntPtr.Zero))
    {
        if (StartDocPrinter(hPrinter, 1, di))
        {
            if (StartPagePrinter(hPrinter))
            {
                bSuccess = WritePrinter(hPrinter, pBytes, dwCount, out dwWritten);
                EndPagePrinter(hPrinter);
            }
            EndDocPrinter(hPrinter);
        }
        ClosePrinter(hPrinter);
    }

    if (bSuccess == false)
        dwError = Marshal.GetLastWin32Error();
    return bSuccess;
}

public static bool SendBytesToPrinter(string printerName, byte[] bytes, string docName)
{
    int dwCount = bytes.Length;
    IntPtr ptrBytes = Marshal.AllocCoTaskMem(Marshal.SizeOf(typeof(byte)) * bytes.Length);
    try
    {
        Marshal.Copy(bytes, 0, ptrBytes, bytes.Length);
        SendBytesToPrinter(printerName, ptrBytes, dwCount, docName);
    }
    finally { Marshal.FreeCoTaskMem(ptrBytes); }
    return true;
}

public static bool SendStringToPrinter(string printerName, string str, string docName)
{
    int dwCount = str.Length;
    IntPtr ptrBytes = Marshal.StringToCoTaskMemAnsi(str);
    try { SendBytesToPrinter(printerName, ptrBytes, dwCount, docName); }
    finally { Marshal.FreeCoTaskMem(ptrBytes); }
    return true;
}

我找到了答案！这不是我的代码，而是 CodePage 1258 的限制（请参阅将文本转换为拉丁文编码并解码越南语的问题).

问题仍然存在，如何用越南语打印？

有一个名叫 HICULIN 的人设法解决了这个问题（参见将 Unicode 字符打印到 POS 打印机）。希望他能与我们分享他的代码。

干杯， 山姆