为什么XPathSelectElements()返回false?

请考虑以下代码段:

var xpath = "//i[@a='1']";
var item = new XElement("i",
    new XAttribute("a", "1"),
    new XAttribute("b", "2"),
    new XAttribute("c", "3"));

Console.WriteLine(item); // <i a="1" b="2" c="3" />
Console.WriteLine("{0} = {1}", xpath, item.XPathSelectElements(xpath).Any());

我正期待着 .Any() true ,但我一直 false .