Windows GDI 打印机错误 StartDocPrinter

Question

实际上我正在使用 Qt 打印，需要将 RAW 命令（ESCP 命令）发送到打印机。经过一番搜索，我发现我需要使用 Windows API 来做到这一点。

参考这个帖子：win32-c-print-string-to-printer

我创建了如下代码：

const QString pName = "EPSON LX-300+ /II";
LPBYTE lpData;
BOOL bStatus = FALSE;
HANDLE hPrinter = NULL;
DOC_INFO_1 DocInfo;
DWORD dwPrtJob = 0L;
DWORD dwBytesWritten = 0L;
LPTSTR printerName = new wchar_t[pName.length() + 1];
pName.toWCharArray(printerName);
printerName[pName.length()] = '\0';
QString so = "\x1b@Is it works?";
QByteArray ba = so.toUtf8();
lpData = (unsigned char*)(ba.data());
DWORD dwCount = ba.length();
qDebug() << so;

bStatus = OpenPrinter(printerName, &hPrinter, NULL);
if(bStatus) {
    DocInfo.pDocName = (LPTSTR)_T("My Document");
    DocInfo.pOutputFile = NULL;
    DocInfo.pDatatype = (LPTSTR)_T("RAW");
    dwPrtJob = StartDocPrinter (
                    hPrinter,
                    1,
                    (LPBYTE)&DocInfo);
    qDebug() << GetLastError();
    if (dwPrtJob > 0) {
            qDebug() << "COMMAND";
            // Send the data to the printer.
            bStatus = WritePrinter (
            hPrinter,
            lpData,
            dwCount,
            &dwBytesWritten);
    }
    qDebug() << dwCount;
    qDebug() << dwBytesWritten;

    EndDocPrinter (hPrinter);

    // Close the printer handle.
    bStatus = ClosePrinter(hPrinter);
    qDebug() << bStatus;
}

if (!bStatus || (dwCount != dwBytesWritten)) {
    bStatus = FALSE;
} else {
    bStatus = TRUE;
}

delete printerName;

并且代码在 StartDocPrinter 上失败，它返回 0 表示失败。使用GetLastError()，函数返回1804。参考this，错误为ERROR_INVALID_DATATYPE。我不确定它是什么错误。我尝试使用不同的 DocInfo.pDatatype 到“RAW”、“TEXT”和“XPS_PASS”，结果是一样的。

有什么办法可以解决吗？

Answer 1

DOC_INFO_1 DocInfo;
DocInfo.pDocName = (LPTSTR)_T("My Document");
DocInfo.pOutputFile = NULL;
DocInfo.pDatatype = (LPTSTR)_T("RAW");

这个铸造归结为

DocInfo.pDocName = (wchar_t*)L"My Document";
...

pDocName 被声明为wchar_t* 这是错误的，演员只是隐藏了错误和警告。尽量避免使用 Microsoft T 宏，这些宏已经过时且无用。请改用 C++ char 和 wchar_t*。要在 Windows 中声明 UTF16 宽字符字符串，请使用 L 前缀。正确用法如下：

DOC_INFO_1 DocInfo;
wchar_t docName[100], dataType[100];
wcscpy_s(docName, 100, L"Print Job");
wcscpy_s(dataType, 100, L"RAW");
DocInfo.pDocName = docName;
DocInfo.pOutputFile = NULL;
DocInfo.pDatatype = dataType;

例子：

const QString pName = "EPSON LX-300+ /II";
wchar_t printerName[100];
pName.toWCharArray(printerName);
pName[pName.length()] = '\0';

HANDLE hprinter;
if (OpenPrinter(printerName, &hprinter, NULL))
{
    DOC_INFO_1 DocInfo;
    wchar_t docName[100], dataType[100];
    wcscpy_s(docName, 100, L"Print Job");
    wcscpy_s(dataType, 100, L"RAW");
    DocInfo.pDocName = docName;
    DocInfo.pOutputFile = NULL;
    DocInfo.pDatatype = dataType;

    DWORD printJob = StartDocPrinter(hprinter, 1, (LPBYTE)&DocInfo);
    if (printJob && StartPagePrinter(hprinter))
    {
        MessageBox(0, L"StartPagePrinter OKAY", 0, 0);
        DWORD written = 0;
        int buflen = 100;
        char *buf = new char[buflen];
        strcpy_s(buf, buflen, "123");
        if (WritePrinter(hprinter, buf, 3, &written))
            MessageBox(0, L"OKAY", 0, 0);
        delete[]buf;
        EndPagePrinter(hprinter);
        EndDocPrinter(hprinter);
    }
    ClosePrinter(hprinter);
}