如何解析存储在字符串中的Xml代码？ [英] How Can I Parse This Xml Code Stored In Strings?

问题描述

i有两个这样的字符串：



string scope =

<？ xml version = \   1.0 \encoding = \UTF-8 \？> + 
  < haspscope> + 
  < hasp type = \\ \\HASP-HL \/> + 
  < / haspscope> ;; 

string format =

 <   haspformat     root   =   \  hasp_info\ > + 
<  功能 > + 
<  属性 < span class =code-attribute>   name   =   \  id \    /  > + 
<  属性   名称  =   \  locked\    /  > + 
<   attribute     name   =   \  expired \    /  > + 
<   attribute    名称  =   \  disabled \    /  > + 
<  属性   名称 < span class =code-keyword> =   \  useful\ < span class =code-attribute>   /  > + 
 <   / feature  >  + 
<   / haspformat  > ; 

被调用的方法接收这两个字符串并返回第三个字符串，如下所示：



字符串结果=

 <？ xml version = < span class =code-string>  1.0 encoding =   UTF-8 ？>  
 <  <跨度class =code-leadattribute> hasp_info  >  
 <  < span class =code-leadattribute> feature     id   =  0   已锁定  =  true   已过期  =  false   已禁用  =  false   可用  =  true    /  >  
 <   feature     id   =   1   已锁定 < span class =code-keyword> =  true   已过期  =  false   已禁用  =  false   可用  =  true    /  >  
 <   / hasp_info  >  

如何获取第二个功能ID的值（它是1 ）？



谢谢

解决方案

所有XML解析器都允许解析存储在字符串中的XML，通过 MemoryString （如果没有直接实现从字符串解析）。这是我对.NET FCL中可用解析器的简短概述：

1. 使用 System.Xml.XmlDocument class。它实现了DOM接口;如果文档的大小不是太大，这种方式是最简单和最好的。
   参见 http://msdn.microsoft.com/en-us/library/system.xml.xmldocument.aspx [ ^ ]。
2. 使用类 System.Xml.XmlTextReader ;这是最快的阅读方式，特别是你需要跳过一些数据。
   参见 http://msdn.microsoft.com/en-us/library/system.xml.xmlreader.aspx [ ^ ]。
3. 使用类 System.Xml.Linq.XDocument ;这是类似于 XmlDocument 的最合适的方式，支持LINQ to XML Programming。
   参见 http://msdn.microsoft.com/en-us/library/system.xml.xmldocument.aspx [ ^ ]，http://msdn.microsoft.com/en-us/library/bb387063.aspx [ ^ ]。

要从流中读取字符串内容，请使用 System.IO.MemoryStream ：

http://msdn.microsoft.com/en-us/library/system .io.memorystream％28v = vs.110％29.aspx [ ^ ]。



放置字符串的代码示例内存流显示在上面引用的MSDN文章中。您只需要在读取之前将流回滚到第一个位置： memStream.Seek（0，SeekOrigin.Begin）; 。从这一点开始，您可以从此流中读取XML。

-SA

一种可能方法是从字符串创建System.Xml.XmlDocument对象，然后找到必要的节点

  var  xml =  new  System.Xml.XmlDocument（）{InnerXml = result}; 
  var  nodes = xml.GetElementsByTagName（ 特征）; 
  var  node = nodes.Cast< XmlElement>（）。SingleOrDefault（e = >  e.GetAttribute（  id）==   1）; 
  if （node！=  null ）
 {
  //  做某事，例如get node.Attributes  
} 

选项＃1使用XmlDocument ...

  string  xml =  <？ xml version = \1.0 \encoding = \UTF-8 \？>< hasp_info>< feature id = \0 \locked = \true \已过期= \false \disabled = \false \useful = \true \/>< feature id = \1 \locked = \true \ expired = \false \disabled = \false \useful = \true \/>< / hasp_info>; 
 System.Xml.XmlDocument xdoc =  new  System.Xml.XmlDocument（）; 
 xdoc.LoadXml（xml）; 
 System.Xml.XmlNode node = xdoc.SelectSingleNode（  // hasp_info / feature [@id =' 1' ]）; 
 
  //  对所选节点执行某些操作 

选项＃2使用LINQ to XML ...

  string  xml =  <？xml version = \1.0 \encoding = \UTF-8 \ ？>< hasp_info>< feature id = \0 \locked = \true \expired = \false \disabled = \false \可用= \\ \\true \/>< feature id = \1 \locked = \true \expired = \false \disabled = \false \useful = \true \/>< / hasp_info>; 
 System.Xml.Linq.XElement doc = System.Xml.Linq.XElement.Parse（xml）; 
 System.Xml.Linq.XElement element =（ from  el  in  doc.Elements（） 
 其中 el.Attribute（  id ）。值==   0 
 选择 el）.FirstOrDefault< System.Xml.Linq.XElement>（）; 
  //  对所选元素执行某些操作 

hi,
i have two strings like this:

string scope =

"<?xml version=\"1.0\" encoding=\"UTF-8\" ?>" + 
"<haspscope>" + 
"    <hasp type=\"HASP-HL\" />" + 
"</haspscope>";

string format =

"<haspformat root=\"hasp_info\">" + 
"    <feature>" + 
"       <attribute name=\"id\" />" + 
"       <attribute name=\"locked\" />" + 
"       <attribute name=\"expired\" />" + 
"       <attribute name=\"disabled\" />" + 
"       <attribute name=\"usable\" />" + 
"    </feature>" + 
"</haspformat>";

the called method receives these two string and returns an third string like this:

string result=

<?xml version="1.0" encoding="UTF-8" ?>
<hasp_info>
  <feature id="0" locked="true" expired="false" disabled="false" usable="true" />
  <feature id="1" locked="true" expired="false" disabled="false" usable="true" />
</hasp_info>

How can i get the value of the second feature id (it's 1) ?

Thanks

解决方案

All XML parsers allow to parse XML stored in a string, via a MemoryString (if parsing from string is not directly implemented). This is my short overview of those parsers available in .NET FCL:

1. Use System.Xml.XmlDocument class. It implements DOM interface; this way is the easiest and good enough if the size if the document is not too big.
   See http://msdn.microsoft.com/en-us/library/system.xml.xmldocument.aspx[^].
2. Use the class System.Xml.XmlTextReader; this is the fastest way of reading, especially is you need to skip some data.
   See http://msdn.microsoft.com/en-us/library/system.xml.xmlreader.aspx[^].
3. Use the class System.Xml.Linq.XDocument; this is the most adequate way similar to that of XmlDocument, supporting LINQ to XML Programming.
   See http://msdn.microsoft.com/en-us/library/system.xml.xmldocument.aspx[^], http://msdn.microsoft.com/en-us/library/bb387063.aspx[^].

For reading a string content from stream, use System.IO.MemoryStream:
http://msdn.microsoft.com/en-us/library/system.io.memorystream%28v=vs.110%29.aspx[^].

The code sample with putting a string to a memory stream is shown in the MSDN article referenced above. You only need to rewind the stream back to the first position before reading: memStream.Seek(0, SeekOrigin.Begin);. From this point, you can read XML from this stream.

—SA

one possible approach is to create System.Xml.XmlDocument object from string and then find the necessary node

var xml = new System.Xml.XmlDocument() {InnerXml = result};
var nodes = xml.GetElementsByTagName("feature");
var node = nodes.Cast<XmlElement>().SingleOrDefault(e => e.GetAttribute("id") == "1");
if (node !=null)
{
   // do something, e.g. get node.Attributes
}

Option #1 using XmlDocument...

string xml = "<?xml version=\"1.0\" encoding=\"UTF-8\" ?><hasp_info><feature id=\"0\" locked=\"true\" expired=\"false\" disabled=\"false\" usable=\"true\" /><feature id=\"1\" locked=\"true\" expired=\"false\" disabled=\"false\" usable=\"true\" /></hasp_info>";
System.Xml.XmlDocument xdoc = new System.Xml.XmlDocument();
xdoc.LoadXml(xml);
System.Xml.XmlNode node = xdoc.SelectSingleNode("//hasp_info/feature[@id = '1']");

// do something with the selected node

Option #2 using LINQ to XML...

string xml = "<?xml version=\"1.0\" encoding=\"UTF-8\" ?><hasp_info><feature id=\"0\" locked=\"true\" expired=\"false\" disabled=\"false\" usable=\"true\" /><feature id=\"1\" locked=\"true\" expired=\"false\" disabled=\"false\" usable=\"true\" /></hasp_info>";
System.Xml.Linq.XElement doc = System.Xml.Linq.XElement.Parse(xml);
System.Xml.Linq.XElement element = (from el in doc.Elements()
                                                where el.Attribute("id").Value == "0"
                                                select el).FirstOrDefault<System.Xml.Linq.XElement>();
// do something with the selected element

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