把ResourceDictionary保存为文件

Uri skinDictUri = new Uri(".\\Resources\\Skins\\skin.xaml", UriKind.Relative);
ResourceDictionary skinDict = Application.LoadComponent(skinDictionaryUri) as ResourceDictionary;

XmlWriter xmlWriter = XmlWriter.Create("c:\\a.xaml");            
XamlWriter.Save(Application.LoadComponent(skinDictionaryUri), xmlWriter);
xmlWriter.Close();

从外部xaml文件加载ResourceDictionary

ResourceDictionary skinDict = new ResourceDictionary();

XmlTextReader txtReader = new XmlTextReader("c:\\a.xaml");
XmlReaderSettings settings = new XmlReaderSettings();
XmlReader xmlReader = XmlReader.Create(txtReader, settings);
skinDict = (ResourceDictionary)XamlReader.Load(xmlReader);