// test xml text writer, correct result
            // output: <?xml version="1.0" encoding="big5"?><root><a/><a/><a/><a/><a/></root>
            {
                Console.WriteLine("Using XmlTextWriter:");

                XmlWriter writer = XmlWriter.Create(Console.Out);
                writer.WriteStartElement("root");
                writer.WriteRaw("<a/><a/><a/><a/><a/>");
                writer.WriteEndElement();
                writer.Flush();

                Console.WriteLine();
                Console.WriteLine();
            }


            // test xml node writer, wrong result
            // output: <?xml version="1.0" encoding="big5"?><root>&lt;a/&gt;&lt;a/&gt;&lt;a/&gt;&lt;a/&gt;&lt;a/&gt;</root>
            {
                Console.WriteLine("Using XmlWellFormedWriter:");

                XmlDocument xmldoc = new XmlDocument();
                XmlWriter writer = xmldoc.CreateNavigator().AppendChild();
                writer.WriteStartElement("root");
                writer.WriteRaw("<a/><a/><a/><a/><a/>");
                writer.WriteEndElement();
                writer.Close();

                xmldoc.Save(Console.Out);
                Console.WriteLine();
                Console.WriteLine();
            }

       /// <summary>
        /// 從 XmlReader 複製到 XmlWriter
        /// </summary>
        /// <param name="reader"></param>
        /// <param name="writer"></param>
        private static void XmlCopyPipe(XmlReader reader, XmlWriter writer)
        {

            if (reader == null)
            {

                throw new ArgumentNullException("reader");

            }

            if (writer == null)
            {

                throw new ArgumentNullException("writer");

            }


            while (reader.Read() == true)
            {
                switch (reader.NodeType)
                {

                    case XmlNodeType.Element:

                        writer.WriteStartElement(reader.Prefix, reader.LocalName, reader.NamespaceURI);

                        writer.WriteAttributes(reader, true);

                        if (reader.IsEmptyElement)
                        {

                            writer.WriteEndElement();

                        }

                        break;

                    case XmlNodeType.Text:

                        writer.WriteString(reader.Value);

                        break;

                    case XmlNodeType.Whitespace:

                    case XmlNodeType.SignificantWhitespace:

                        writer.WriteWhitespace(reader.Value);

                        break;

                    case XmlNodeType.CDATA:

                        writer.WriteCData(reader.Value);

                        break;

                    case XmlNodeType.EntityReference:

                        writer.WriteEntityRef(reader.Name);

                        break;

                    case XmlNodeType.XmlDeclaration:

                    case XmlNodeType.ProcessingInstruction:

                        writer.WriteProcessingInstruction(reader.Name, reader.Value);

                        break;

                    case XmlNodeType.DocumentType:

                        writer.WriteDocType(reader.Name, reader.GetAttribute("PUBLIC"), reader.GetAttribute("SYSTEM"), reader.Value);

                        break;

                    case XmlNodeType.Comment:

                        writer.WriteComment(reader.Value);

                        break;

                    case XmlNodeType.EndElement:

                        writer.WriteFullEndElement();

                        break;

                }
            }
        }

                XmlDocument xmldoc = new XmlDocument();
                XmlWriter writer = xmldoc.CreateNavigator().AppendChild();
                writer.WriteStartElement("root");


                XmlReaderSettings settings = new XmlReaderSettings();
                settings.ConformanceLevel = ConformanceLevel.Fragment;
                XmlReader reader = XmlReader.Create(
                    new StringReader("<a/><a/><a/><a/><a/>"),
                    settings);
                XmlCopyPipe(reader, writer);


                writer.WriteEndElement();
                writer.Close();

                xmldoc.Save(Console.Out);

            XmlDocument xdoc = new XmlDocument();
            xdoc.LoadXml("<root><node1><data/><data/><data/></node1><node2/></root>");

            
            XmlNodeWriter xnw = new XmlNodeWriter(xdoc.DocumentElement, true);

            xnw.WriteStartElement("newNode");
            xnw.WriteAttributeString("newatt", "123");
            xnw.WriteCData("1234567890");
            xnw.WriteEndElement();
            xnw.Close();

            xdoc.Save(Console.Out);

    public class XmlNodeWriter : XmlWriter
    {
        private XmlWriter _inner_writer = null;
        public XmlNodeWriter(XmlNode node, bool clean)
        {
            if (clean == true)
            {
                node.RemoveAll();
            }

            this._inner_writer = node.CreateNavigator().AppendChild();
        }


        #region 無聊的 "延長線" 程式碼...

        // 略! 共一百多行，補上廿幾個 abstract method / property, 把它接到 _inner_writer 上

        #endregion
    }

        public override void Close()
        {
            this._inner_writer.Close();
        }

        public override void Flush()
        {
            this._inner_writer.Flush();
        }

        public override string LookupPrefix(string ns)
        {
            return this._inner_writer.LookupPrefix(ns);
        }

    public abstract class XmlWriterFactory : XmlWriter
    {
        public static XmlWriter Create(XmlNode node)
        {
            return Create(node, false, null);
        }

        public static XmlWriter Create(XmlNode node, bool clearnContent)
        {
            return Create(node, clearnContent, null);
        }

        public static XmlWriter Create(XmlNode node, bool cleanContent, XmlWriterSettings settings)
        {
            if (node == null) throw new ArgumentNullException("node");

            if (cleanContent == true)
            {
                node.RemoveAll();
            }

            XmlWriter xw = node.CreateNavigator().AppendChild();

            if (settings != null)
            {
                xw = XmlWriter.Create(xw, settings);
            }

            return xw;
        }
    }