Get attribute value from c#/xpath

Question

I have an app.config file, and need to get value of an attribute:

<param name="File" value="C:\"/>

Liquid XML Studio gives the following xml:

/configuration/log4net/appender/param[1]

However, what C# code can use xpath to get a value?

Answer 1

Use this XPath:

/configuration/log4net/appender/param[@name='File']/@value

Depending on how you read the XML, the code for using the XPath may differ a bit. If you're using XDocument, you can use the XPathEvaluate extension method like so:

var eval = xml.XPathEvaluate("/configuration/log4net/appender/param[@name='File']/@value");
var value = ((IEnumerable)eval).OfType<XAttribute>().Single().Value;

If you're using XmlDocument, there is a SelectSingleNode() method. And if you use an XPathDocument, you need to compile a XPathExpression and then use this XPath against a navigator.