如何使用xmlite在缓冲区中存储xml？ [英] how can i store xml in buffer using xmlite?

问题描述

我想写缓冲区XmlLite xml数据，但不能有任何api。写一个xml文件工作完美，但在内存流我无法计算
i我正在工作链接api
http://msdn.microsoft.com/en-us/library/ms752901（v = VS.85）.aspx p>

I'm trying to write xml data with XmlLite on buffer but couldn't got any api. writing a xml file works perfect but on a memory stream I can't figure i am working on follwong link api http://msdn.microsoft.com/en-us/library/ms752901(v=VS.85).aspx

推荐答案

您可以使用 SHCreateMemStream 或 CreateStreamOnHGlobal 创建内存流。以下是您提供的示例代码：

You can use either SHCreateMemStream or CreateStreamOnHGlobal to create an memory stream. Here is the sample code for your reference:

CComPtr<IStream> spMemoryStream;
CComPtr<IXmlWriter> spWriter;
CComPtr<IXmlWriterOutput> pWriterOutput;

// Opens writeable output stream.
spMemoryStream.Attach(::SHCreateMemStream(NULL, 0));
if (spMemoryStream == NULL)
    return E_OUTOFMEMORY;

// Creates the xml writer and generates the content.
CHKHR(::CreateXmlWriter(__uuidof(IXmlWriter), (void**) &spWriter, NULL));
CHKHR(::CreateXmlWriterOutputWithEncodingName(spMemoryStream,
    NULL, L"utf-16", &pWriterOutput));
CHKHR(spWriter->SetOutput(pWriterOutput));
CHKHR(spWriter->SetProperty(XmlWriterProperty_Indent, TRUE));
CHKHR(spWriter->WriteStartDocument(XmlStandalone_Omit));
CHKHR(spWriter->WriteStartElement(NULL, L"root", NULL));
CHKHR(spWriter->WriteWhitespace(L"\n"));
CHKHR(spWriter->WriteCData(L"This is CDATA text."));
CHKHR(spWriter->WriteWhitespace(L"\n"));
CHKHR(spWriter->WriteEndDocument());
CHKHR(spWriter->Flush());

// Allocates enough memeory for the xml content.
STATSTG ssStreamData = {0};
CHKHR(spMemoryStream->Stat(&ssStreamData, STATFLAG_NONAME));
SIZE_T cbSize = ssStreamData.cbSize.LowPart;
LPWSTR pwszContent = (WCHAR*) new(std::nothrow) BYTE[cbSize + sizeof(WCHAR)];
if (pwszContent == NULL)
    return E_OUTOFMEMORY;

// Copies the content from the stream to the buffer.
LARGE_INTEGER position;
position.QuadPart = 0;
CHKHR(spMemoryStream->Seek(position, STREAM_SEEK_SET, NULL));
SIZE_T cbRead;
CHKHR(spMemoryStream->Read(pwszContent, cbSize, &cbRead));
pwszContent[cbSize / sizeof(WCHAR)] = L'\0';

wprintf(L"%s", pwszContent);

XmlLite的一个漂亮的事情是它与IStream接口。它真的不在乎流是什么样的背后的场景。

One pretty thing about XmlLite is it works with IStream interface. It really doesn't care what exactly the stream looks like behind the scene.

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