How Can I Parse This Xml Code Stored In Strings?

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hi,
i have two strings like this:

string scope =

HTML

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

string format =

HTML

"<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

<?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

Posted 4-Feb-14 6:03am

DrooBo

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Sergey Alexandrovich Kryukov 4-Feb-14 12:34pm

What have you tried so far?
—SA

4 solutions

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Sergey Alexandrovich Kryukov · Answer 1 · 2014-02-04T06:34:00

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:

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[^].
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[^].
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

Alexander Sharykin · Answer 2 · 2014-02-04T07:05:00

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

C#

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
}

idenizeni · Answer 3 · 2014-02-04T07:15:00

Option #1 using XmlDocument...

C#

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...

C#

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

DrooBo · Answer 4 · 2014-02-05T04:29:00

actually my c# code to read my output string is:

XmlReader reader = XmlReader.Create(new StringReader(result));
reader.MoveToElement();
reader.MoveToAttribute("id");
string firstId = reader.Value;
reader.MoveToAttribute("id");
string secondId = reader.Value;
Debug.WriteLine("first: "+firstId+"\t second: "+secondId);

but it doesn't works.
I need to get the value of the second attribute "id" and save it in a string.
(Example: i need to save value '1' in a string)

Thanks

How Can I Parse This Xml Code Stored In Strings?

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