问XElement和XslCompiledTransform的问题

EN

static void Main(string[] args)
{
    XslCompiledTransform stylesheet = GetStylesheet(); // not shown for brevity
    IXPathNavigable input = this.GetXElementXml();
    using (MemoryStream ms = this.TransformXml(input, stylesheet))
    {
        XmlReader xr = XmlReader.Create(ms);
        xr.MoveToContent();
    }
}

private MemoryStream TransformXml(
    IXPathNavigable xml,
    XslCompiledTransform stylesheet)
{
    MemoryStream transformed = new MemoryStream();
    XmlWriter writer = XmlWriter.Create(transformed);
    stylesheet.Transform(xml, null, writer);

    transformed.Position = 0;
    return transformed;
}

private IXPathNavigable GetXElementXml()
{
    var xml = new XElement("x", new XElement("y", "sds"));
    return xml.CreateNavigator();
}

private IXPathNavigable GetXmlDocumentXml()
{
    var xml = new XmlDocument();
    xml.LoadXml("<x><y>sds</y></x>");
    return xml.CreateNavigator();
}