DataSet与xml文件的互相转换

http://www.cnblogs.com/long2006sky/articles/1258731.html
DataSet转换为xml文件
//将DataSet转换为xml文件
        private static void ConvertDataSetToXMLFile(DataSet xmlDS, string xmlFile)
        {
            MemoryStream stream = null;
            XmlTextWriter writer = null;
           
            try
            {
                stream = new MemoryStream();
                //从stream装载到XmlTextReader
                writer = new XmlTextWriter(stream, Encoding.Unicode);
                //用WriteXml方法写入文件.
                xmlDS.WriteXml(writer);
                int count = (int)stream.Length;
                byte[] arr = new byte[count];
                stream.Seek(0, SeekOrigin.Begin);
                stream.Read(arr, 0, count);
                //返回Unicode编码的文本