XDocument输出

使用XDocument时,用普通的ToString方式无法输出声明,可以按如下方式输出声明

    var doc = new XDocument(
            new XDeclaration("1.0", "utf-16", "yes"),
            new XElement("blah", "blih"));

    var wr = new StringWriter();
    doc.Save(wr);
    Console.Write(wr.GetStringBuilder().ToString());