title: Iterating through an Amazon-specific XDocument
body: <p>I'm working with the Amazon Advertising API, which returns XML as demonstrated in this fiddle: <a href="http://xopusfiddle.net/27NxH/" rel="nofollow noreferrer">http://xopusfiddle.net/27NxH/</a></p>
  
  <p>I'm looking to get the value of the item as offered by Amazon, where it exists. In theory, the following should return an XML node with the name of <code>Amount</code> and the value of <code>9980</code></p>
  
  <pre><code>string uri = "redacted" + isbn;
  string signedUri = helper.Sign(uri);
  WebRequest request = HttpWebRequest.Create(signedUri);
  WebResponse response = request.GetResponse();
  XmlDocument xDoc = new XmlDocument();
  xDoc.Load(response.GetResponseStream());
  var testvar = xDoc.SelectSingleNode("/ItemLookupResponse/Items/Item/ItemAttributes/ListPrice");
  </code></pre>
  
  <p>However, <code>testvar</code> returns <code>null</code>. The same occurs when I attempt to return an <code>XmlNodeList</code> also.</p>
  
  <p>I've checked that there is indeed an XML document loaded (there is), and I've noticed that the following will return the correct node (<code>Amount</code>) with a value of <code>9980</code>:</p>
  
  <pre><code>XmlNode aznPriceNode = xDoc.DocumentElement.ChildNodes.Item(1).ChildNodes.Item(1).ChildNodes.Item(8).ChildNodes.Item(10).ChildNodes.Item(0);
  </code></pre>
  
  <p>However, hardcoding such a path is a terrible idea, and doesn't always work since the XML document might not always contain a <code>ListPrice</code> entry.</p>
  
  <p>Why doesn't XPath work in this instance?</p>