I've got a problem reading in and searching through data where the
attributes might contain both single and/or double quotes. As they get
inserted into an XmlDocument, they get marked up with " and
' properly (which I can tell by looking at OuterXML), but then
using xPath to search for them is proving to be inconsistent. It's
like I can only write code that works for either double or single
quotes at time, depending on what I use to surround the data in the
query in the first place. All would be fine if using marked up code in
my queries worked, but it doesn't. So anyone know why this code
doesn't work:

XmlDocument xd = new XmlDocument();
XmlElement xe = xd.CreateElement("Element");
xe.SetAttribute("Attr", "Hello 'world'");
xd.AppendChild(xe);

xd.SelectSingleNode("//Element[@Attr=\"Hello 'world'\"]");
xd.SelectSingleNode("//Element[@Attr=\"Hello 'world'\"]");


The first select works fine, but the second one fails. I'm led to
believe that they're a direct equivalent, so what's happening here?

Thanks for any help!