why doesn't XElement have a ToDictionary linq expression?

For some reason ToDictionary isn't working.

开发者_如何学运维I am using vs.net 2010 and 4.0

XElement root = XElement.Load(fullPathToXml);            
IEnumerable<XElement> nodes = root.Elements("root");

var dic = nodes.ToDictionary(...)

I want to convert it to a dictionary<string,string>

it says there is no defintion for 'ToDictionary'...?

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Add

using System.Linq;