DataSet(DataTable)与XML互转

加引用：

using System;     using System.Data;     using System.IO;     using System.Xml;     using System.Text;     // 相应C#代码：     private string ConvertDataTableToXML(DataTable xmlDS)     {         MemoryStream stream = null;         XmlTextWriter writer = null;         try         {             stream = new MemoryStream();             writer = new XmlTextWriter(stream, Encoding.Default);             xmlDS.WriteXml(writer);             int count = (int)stream.Length;             byte[] arr = new byte[count];             stream.Seek(0, SeekOrigin.Begin);             stream.Read(arr, 0, count);             UTF8Encoding utf = new UTF8Encoding();             return utf.GetString(arr).Trim();         }         catch         {             return String.Empty;         }         finally         {             if (writer != null) writer.Close();         }     }      private DataSet ConvertXMLToDataSet(string xmlData)     {       StringReader stream = null;       XmlTextReader reader = null;       try       {         DataSet xmlDS = new DataSet();         stream = new StringReader(xmlData);         reader = new XmlTextReader(stream);         xmlDS.ReadXml(reader);         return xmlDS;       }       catch (Exception ex)       {         string strTest = ex.Message;         return null;       }       finally       {         if (reader != null)         reader.Close();       }     }