SelectSingleNode returns the wrong Node instance value

Question

I am parsing some XML. I am iterating over 2 Pit nodes and trying to find out their x node value.

My problem: When I inspect each Pit nodes x value its always says value is 8, when the second nodes x value is actually 1.

Why is this happening and how can I fix it?

XmlNodeList xNodes = xdoc.DocumentElement.SelectNodes("//ns:pits", nsmgr);

foreach (XmlNode pit in xNodes) {
    XmlNode x = pit.SelectSingleNode("//ns:x", nsmgr);
    MessageBox.Show(x.InnerText, "");  // Always prints "8", when 1 should be "8", another "1"
}

The data I am using:

<?xml version="1.0"?>
<xml12d>
    <pit>
      <x>8.89268569</x>
      <y>1.26122586</y>
      <z>1.62414621</z>
    </pit>
    <pit>
      <x>1.09268598</x>
      <y>7.24091243</y>
      <z>8.20896044</z>
    </pit>
</xml12d>

Answer 1

The XPath // is an abbreviated syntax to select any descendant from the document root. //ns:x will select every ns:x in the document -- it isn't scoped to its parent node as a root -- so using it with SelectSingleNode will always select the first ns:x in the document.

If you change the XPath to simply ns:x, which will select only child ns:x, it should work.

You can actually get rid of the second XPath call by modifying the first to select //ns:pits/ns:x[1], which will select the first ns:x child of every ns:pits in the document.