XML 解析器，多个根 [英] XML parser, multiple roots

问题描述

这是输入字符串的一部分，我无法修改它，它总是以这种方式出现(通过共享内存)，但是我当然可以在将其放入字符串后进行修改:

SCPUCLKCPU Clock2930;SCPUMUL</id><label>CPU乘数</label><value>11.0</value></sys><sys><id>SCPUFSB</id><label>CPU FSB<;/label>266

我都读过它:

 String.Concat(XElement.Parse(encoding.GetString(bytes)).后代(价值").Select(v => v.Value));

和:

 XmlDocument 文档 = new XmlDocument();document.LoadXml(encoding.GetString(bytes));XmlNode node = document.DocumentElement.SelectSingleNode("//value");Console.WriteLine("node = " + node);

但是它们在运行时都出现错误；输入有多个根(有多个根元素引用)，我不想分割字符串.

他们有什么方法可以读取字符串，在 和 之间取值而不将字符串分成多个输入?

解决方案

这不是一个格式良好的 XML 文档，因此大多数 XML 工具将无法处理它.

一个例外是 XmlReader.查找 XmlReaderSettings.ConformanceLevel 在 MSDN 中.如果将其设置为 ConformanceLevel.Fragment，则可以使用这些设置创建 XmlReader 并使用它从没有顶级元素的流中读取元素.>

您必须编写使用 XmlReader.Read() 的代码来执行此操作 - 您不能仅将其提供给 XmlDocument(这确实需要单个顶级元素).

例如

var readerSettings = new XmlReaderSettings { ConformanceLevel = ConformanceLevel.Fragment };使用 (var reader = XmlReader.Create(stream, readerSettings)){而 (reader.Read()){使用 (var fragmentReader = reader.ReadSubtree()){如果 (fragmentReader.Read()){var fragment = XNode.ReadFrom(fragmentReader) as XElement;//用片段做一些事情}}}}

This is part of the input string, i can't modify it, it will always come in this way(via shared memory), but i can modify after i have put it into a string of course:

<sys><id>SCPUCLK</id><label>CPU Clock</label><value>2930</value></sys><sys><id>SCPUMUL</id><label>CPU Multiplier</label><value>11.0</value></sys><sys><id>SCPUFSB</id><label>CPU FSB</label><value>266</value></sys>

i've read it with both:

        String.Concat(
            XElement.Parse(encoding.GetString(bytes))
                .Descendants("value")
                .Select(v => v.Value));

and:

    XmlDocument document = new XmlDocument();
    document.LoadXml(encoding.GetString(bytes));
    XmlNode node = document.DocumentElement.SelectSingleNode("//value");
    Console.WriteLine("node = " + node);

but they both have an error when run; that the input has multiple roots(There are multiple root elements quote), i don't want to have to split the string.

Is their any way to read the string take the value between <value> and </value> without spiting the string into multiple inputs?

解决方案

That's not a well-formed XML document, so most XML tools won't be able to process it.

An exception is the XmlReader. Look up XmlReaderSettings.ConformanceLevel in MSDN. If you set it to ConformanceLevel.Fragment, you can create an XmlReader with those settings and use it to read elements from a stream that has no top-level element.

You have to write code that uses XmlReader.Read() to do this - you can't just feed it to an XmlDocument (which does require that there be a single top-level element).

e.g.,

var readerSettings = new XmlReaderSettings { ConformanceLevel = ConformanceLevel.Fragment };
using (var reader = XmlReader.Create(stream, readerSettings))
{
    while (reader.Read())
    {
        using (var fragmentReader = reader.ReadSubtree())
        {
            if (fragmentReader.Read())
            {
                var fragment = XNode.ReadFrom(fragmentReader) as XElement;

                // do something with fragment
            }
        }
    }
}

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