//将xml对象内容字符串转换为DataSet

        public static DataSet ConvertXMLToDataSet(string xmlData)

        {

            StringReader stream = null;

            XmlTextReader reader = null;

            try

            {

                DataSet xmlDS = new DataSet();

                stream = new StringReader(xmlData);

                //从stream装载到XmlTextReader

                reader = new XmlTextReader(stream);

                xmlDS.ReadXml(reader);

                return xmlDS;

            }

            catch (System.Exception ex)

            {

                throw ex;

            }

            finally

            {

                if (reader != null)

                    reader.Close();

            }

        }

 

        //将xml文件转换为DataSet

        public static DataSet ConvertXMLFileToDataSet(string xmlFile)

        {

            StringReader stream = null;

            XmlTextReader reader = null;

            try

            {

                XmlDocument xmld = new XmlDocument();

                xmld.Load(xmlFile);

 

                DataSet xmlDS = new DataSet();

                stream = new StringReader(xmld.InnerXml);

                //从stream装载到XmlTextReader

                reader = new XmlTextReader(stream);

                xmlDS.ReadXml(reader);

                //xmlDS.ReadXml(xmlFile);

                return xmlDS;

            }

            catch (System.Exception ex)

            {

                throw ex;

            }

            finally

            {

                if (reader != null)

                    reader.Close();

            }

        }

 

        //将DataSet转换为xml对象字符串

        public static string ConvertDataSetToXML(DataSet xmlDS)

        {

            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);

 

                UnicodeEncoding utf = new UnicodeEncoding();

                return utf.GetString(arr).Trim();

            }

            catch (System.Exception ex)

            {

                throw ex;

            }

            finally

            {

                if (writer != null)

                    writer.Close();

            }

        }

 

        //将DataSet转换为xml文件

        public 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

                UnicodeEncoding utf = new UnicodeEncoding();

                StreamWriter sw = new StreamWriter(xmlFile);

                sw.WriteLine("<?xml version=\"1.0\" encoding=\"utf-8\"?>");

                sw.WriteLine(utf.GetString(arr).Trim());

                sw.Close();

            }

            catch (System.Exception ex)

            {

                throw ex;

            }

            finally

            {

                if (writer != null)

                    writer.Close();

            }

        }

https://www.cnblogs.com/marsli/p/4121441.html