不包含＆＃34; XmlXapResolver＆＃34;的定义在Windows Phone8.1中

Question

＆＃34; XmlXapResolver＆＃34;是在wp8中工作，但在WP8.1中不工作，并使用System.Xml添加名称空间＆＃34;＆＃34;

public static string GetAppAttribute(string attributeName)
    {
        string attribute;
        try
        {
            XmlReaderSettings settings2 = new XmlReaderSettings
            {
                XmlResolver = new XmlXapResolver()

            };
            XmlReaderSettings settings = settings2;
            using (XmlReader reader = XmlReader.Create("WMAppManifest.xml", settings))
            {
                reader.ReadToDescendant("App");
                if (!reader.IsStartElement())
                {
                    throw new FormatException("WMAppManifest.xml is missing App");
                }
                attribute = reader.GetAttribute(attributeName);
            }
        }