Question

我正在尝试打开内存流以与xmllite库一起使用。写一个可以正常工作，但从一个人那里读书给我带来了困难。下面是我正在使用的代码。基本上我创建一个默认的xml字符串（LPWSTR）并使用CreateStreamOnHGlobal将其写入内存流。然后我寻求开始并回读它以确保它在那里（它是）。然后我再次寻找并将其分配给读者的输入。它永远不会越过界限：

while (S_OK == (hr = pReader->Read(&nodeType)))

我得到一个XmlNodeType_None和一个HRESULT值-1072894427。我相信它在阅读流时遇到了麻烦，但我不确定。如果我使用文件流代替相同的代码，并且从内存流写入xml也可以正常工作

HRESULT hr = S_OK;  CComPtr<IStream> pStream = NULL;
IXmlReader *pReader = NULL;
XmlNodeType nodeType;

LPWSTR pwszXMLString = 
    L"<?xml version\"1.0\" encoding=\"UTF-8\" ?>\r\n"
    L"<paramlist name=\"LP\">\r\n"
        L"<value></value>\r\n"
        L"<value></value>\r\n"
    L"</paramlist>\r\n"
    L"<param name=\"AutoConnect\">false</param>\r\n"
    L"<param name=\"ConnectWhenLit\">false</param>\r\n"
    L"<param name=\"SessionMaxBytes\">200000</param>\r\n"
    L"<param name=\"SessionTimeoutSecs\">300</param>\r\n"
    L"<param name=\"PacketDelayMs\">0</param>\r\n"
    L"<param name=\"PacketSizeBytes\">4096</param>\r\n"
    L"<param name=\"LowSSLSecurity\">true</param>\r\n";

DWORD dwWritten = 0;
hr = CreateStreamOnHGlobal(NULL, FALSE, &pStream);
hr = pStream->Write(pwszXMLString, wcslen(pwszXMLString) * sizeof(WCHAR), &dwWritten);

// print out the contents of the memory stream just to make sure we have it
LARGE_INTEGER pos;
pos.QuadPart = 0;
pStream->Seek(pos, STREAM_SEEK_SET, NULL);
STATSTG ssStreamData = {0};
pStream->Stat(&ssStreamData, STATFLAG_NONAME);
SIZE_T cbSize = ssStreamData.cbSize.LowPart;
LPWSTR pwszContent = (WCHAR*) new BYTE[cbSize + sizeof(WCHAR)];
if (pwszContent == NULL)
    return E_OUTOFMEMORY;

pStream->Seek(pos, STREAM_SEEK_SET, NULL);
SIZE_T cbRead;
pStream->Read(pwszContent, cbSize, &cbRead);
pwszContent[cbSize/sizeof(WCHAR)] = L'\0';

CZString czContent;
czContent.LoadWideString(pwszContent, cbSize);
wprintf(L"%S", czContent.GetString().c_str());
pStream->Seek(pos, STREAM_SEEK_SET, NULL);

if (hr == S_OK)
{
    typedef HRESULT (WINAPI *CreateXmlReaderFunc)(const IID & riid, void** ppvObject, IMalloc * pMalloc);
    CreateXmlReaderFunc _CreateXmlReaderFunc = (CreateXmlReaderFunc)GetProcAddress(m_hXMLLite, "CreateXmlReader");

    if (FAILED(hr = _CreateXmlReaderFunc(__uuidof(IXmlReader), (void**) &pReader, NULL)))
    {
        MessageBox(NULL, CStringHelper::Format(L"Error: GetProcAddress() failed to find 'CreateXmlReader' %d\n", GetLastError()).c_str(), L"Error", MB_OK);
        return -1;
    }

    pReader->SetInput(pStream);
}

while (S_OK == (hr = pReader->Read(&nodeType))) 
{
    switch (nodeType) 
    {
                    // parse xml here
    }
}
return 0;

Answer 1

您的xml字符串不正确。 “版本”和“1.0”之间必须有“=”。其次，字符串使用UTF-16，而标题表示它是UTF-8。在标头中将UTF-8更改为UTF-16或删除编码属性。任

LPWSTR pwszXMLString = 
L"<?xml version=\"1.0\" encoding=\"UTF-16\" ?>\r\n"

或

LPWSTR pwszXMLString = 
L"<?xml version=\"1.0\"?>\r\n"

作品。

无法使用内存缓冲区使用xmllite读取xml字符串

1 个答案: