Utility for determining the XPath of a given node

XPathHelp.cs

using System;
using System.Text;
using System.Xml;
using System.Xml.XPath;

public static class XPathHelp
{

  public static string GetXPathForNode(XmlNode node)
  {
    return GetXPathForNode(node.CreateNavigator());
  }

  public static string GetXPathForNode(XPathNavigator node)
  {
    StringBuilder sb = new StringBuilder();
    BuildNodeXPath(node, sb);
    return sb.ToString();
  }

  private static void BuildNodeXPath(XPathNavigator node, StringBuilder sb)
  {
    if (node.NodeType == XPathNodeType.Root)
    {
      sb.Append("/");
      return;
    }

    XPathNavigator treeWalk = node.Clone();
    if (treeWalk.MoveToParent())
    {
      if (treeWalk.NodeType != XPathNodeType.Root)
        BuildNodeXPath(treeWalk, sb);
    }

    sb.AppendFormat("/{0}", XPathNodeName(node));

    XPathNavigator nodeParent = node.Clone();
    nodeParent.MoveToParent();

    XPathNodeIterator siblings = node.NodeType == XPathNodeType.Element
                                   ? nodeParent.SelectChildren(node.LocalName, node.NamespaceURI)
                                   : nodeParent.SelectChildren(node.NodeType);

    if (siblings.Count < 2) return;
    do
    {
      if (siblings.Current.ComparePosition(node) != XmlNodeOrder.Same) continue;
      sb.AppendFormat("[{0}]", siblings.CurrentPosition);
      break;
    } while (siblings.MoveNext());

  }

  public static string XPathNodeName(XmlNode node)
  {
    return XPathNodeName(node.CreateNavigator());
  }

  public static string XPathNodeName(XPathNavigator node)
  {
    switch (node.NodeType)
    {
      case XPathNodeType.Attribute:
        return String.Format("@{0}", node.Name);
      case XPathNodeType.Comment:
        return "comment()";
      case XPathNodeType.Element:
        return node.Name;
      case XPathNodeType.Namespace:
        return String.Format("namespace::{0}", node.Name);
      case XPathNodeType.ProcessingInstruction:
        return String.Format("processing-instruction(\"{0}\")", node.Name);
      case XPathNodeType.Text:
        return "text()";
      default:
        System.Diagnostics.Debugger.Break();
        return String.Format("{{{0}}}", node.NodeType);
    }
  }

}