title: Using xpathnavigator select xpathexpression response by concatenating a constant
body: <p>I have a library function which looks as below</p>
  
  <pre><code>private static string Parse(XPathNavigator xNav, XPathExpression xPathExpression)
      {
          string result = string.Empty;
          XPathNodeIterator xpathIterator = xNav.Select(xPathExpression.Clone());
  
          while (xpathIterator.MoveNext())
          {
              result = result + xpathIterator.Current.TypedValue + "#";
          }
  
          return result;
      }
  </code></pre>
  
  <p>And there is a XML file which would look as below</p>
  
  <pre><code>&lt;Account account_no ="100"&gt;
  &lt;Name&gt;Hello&lt;/Name&gt;
  &lt;/Account&gt; 
  </code></pre>
  
  <p>Now I need write a xpath which would  return account_no concatenating some constant</p>
  
  <p>I wrote code something like below</p>
  
  <pre><code>        XPathDocument doc = new XPathDocument(@"..\..\test.xml", XmlSpace.Default);
          XPathNavigator xNav = doc.CreateNavigator();
          string xpath = "concat('Account No', /Account/@account_no)";
          XPathExpression xPathExpression = XPathExpression.Compile(xpath);
          string result = Parse(xNav, xPathExpression);
  </code></pre>
  
  <p>The result what I am expecting is account_no prefixing it with some text constant. So I wrote the xpath as concat('Account No', /Account/@account_no). But this did not work, failed at xNav.Select(). Please help me on how to write proper xpath to get the required result. I do not have liberty to make changes to parse function, whatever I can do, I should do with only xpath string.</p>
  
  <p>Thank you.</p>