public static void Save()
{
XDocument xDoc = new XDocument();
XElement rootNode = new XElement("UserSetting");
rootNode.Add(FavoriteManager.CreateXElementByPageIndex());
rootNode.Add(ProjectFileManager.CreateXElementByRecentUsedProjects());
rootNode.Add(GlobalSetting.CreateXELementBySetting());
rootNode.Add(Simulation.Core.Global.GlobalSetting.CreateXELementBySetting());
xDoc.Add(rootNode);
xDoc.Save(dir + @"\UserSetting.xml");
}