检查：

Check this:

string folder = "Quality";
var subfolders = myxml.Root.Elements("Folder")
		.Where(x=>x.Attribute("name").Value==folder)
		.SelectMany(x=>x.Elements("subfolder")
                                .Select(y=>y.Attribute("name").Value))
		.ToList();

结果：

Result:

Quality1 
Quality2 
Quality3 
Quality4