XML node doesn't exist?

This is from a small personal project using Amazon webservices. It's a pretty simple windows form desktop app that uses Linq to SQL. 

Dealing with some evil XML from Amazon that seems to have several variations. In some responses the node is there, other responses the node doesn't exist and is called something else (for pretty much the same data). I'm being lazy and pulling out the data I need one node at a time which can be a problem when the nodes are not present.

To get around this, for the nodes that I know to be problematic, I needed to check that the node was actually going to be available before doing the convert. I do this by looking at the exact node and check if it's null.

doc.GetElementsByTagName("TotalReviews").Item(0) != null

If you just look at the  doc.GetElementsByTagName("TotalReviews") != null it won't return null, but will fall over because there are no items to pull data from. I think when I looked at it it returned '0'. Anyway, you need the Item(0) as this is the value you are doing .InnerText on.

I'm using the GetElementsByTagName as it's generally easier than a longwinded xpath, but in some cases this is just not appropriate. A few cases I've selected children nodes by their position. I know this code isn't pretty, it probably isn't the best way to do thing, but it works.

using System.Xml;

WebRequest request = HttpWebRequest.Create(url);
WebResponse response = request.GetResponse();
doc.Load(response.GetResponseStream());
               
//If in doubt, spit the xml out somewhere and look at the payload
// doc.Save(Console.Out);
...

 if (doc.GetElementsByTagName("TotalReviews").Item(0) != null)
{
      book.NumOfReviews = Convert.ToInt32(doc.GetElementsByTagName("TotalReviews").Item(0).InnerText);
}
 else if (doc.GetElementsByTagName("TotalFeedback").Item(0) != null)
 {
      book.NumOfReviews = Convert.ToInt32(doc.GetElementsByTagName("TotalFeedback").Item(0).InnerText);
 }
     else
 {
        book.NumOfReviews = 0;
 }

...