<BaseInfo>
  <TransType>U</TransType> 
  <TransCode>01011001</TransCode> 
  <HeaderVervsion /> 
  <SubTransCode /> 
  <TransDate>2011-06-16</TransDate> 
  <TransTime>00:00:00</TransTime> 
  <TransSeq /> 
  <Operator>001</Operator> 
  <TotalRowNum /> 
  <RowNumStart /> 
  <ResultCode>0</ResultCode> 
  <ResultMsg /> 
  <CltSysCode>13</CltSysCode> 
  <ClinetIp /> 
  <MachineNo /> 
  <OperatorCom>86</OperatorCom> 
  <SvrSysCode /> 
  <RouteKey1 /> 
  <RouteKey2 /> 
  <RouteKey3 /> 
  <RegCertifId /> 
  <TransEndDATE /> 
  <TransEndTime /> 
  <ValConstrLimit1 /> 
  <ValConstrLimit2 /> 
  <GranterNo /> 
  <GranterPwd /> 
  <BS_NO /> 
  <EXT_KEY1 /> 
  <EXT_KEY2 /> 
  <EXT_KEY3 /> 
- <Input>
- <Base>
  <GUID>NCIA30888664887549x</GUID> 
  <ManageCom>86210000</ManageCom> 
  <PayMode /> 
  <HighAmntFlag /> 
  <HealthImpartFlag /> 
  <OccpuImpartFlag /> 
  <FinImpartFlag /> 
  </Base>
  </Input>
  </BaseInfo>

string sqlBaseInfo = "select * from BaseInfo where BaseInfo_Id = 14";
        dt = DBHelper.getDataTable(sqlBaseInfo, null);
        dt.TableName = "BaseInfo";
        ds.Tables.Add(dt.Copy());
        //----------------------
        string sqlInput = "select * from Input where BaseInfo_Id = 14";
        DataTable dtInput = DBHelper.getDataTable(sqlInput, null);
        dtInput.TableName = "Input";
        string Input_Id = dtInput.Rows[0]["Input_Id"].ToString();
        ds.Tables.Add(dtInput.Copy());

        
        //---------------------
        string sqlBase = "select * from Base where Input_Id = " + Input_Id + "";
        dt = DBHelper.getDataTable(sqlBase, null);
        dt.TableName = "Base";
        ds.Tables.Add(dt.Copy());
       DataRelation custOrderRelation = ds.Relations.Add("Input-Base", ds.Tables["Input"].Columns["Input_Id"], ds.Tables["Base"].Columns["Input_Id"]);
       DataRelation custOrderRelation1 = ds.Relations.Add("BaseInfo-Input", ds.Tables["BaseInfo"].Columns["BaseInfo_Id"], ds.Tables["Input"].Columns["BaseInfo_Id"]);

   public static bool CDataToXmlFile(DataTable dt, string xmlFilePath)
    {
        if ((dt != null) && (!string.IsNullOrEmpty(xmlFilePath)))
        {
           // string path = HttpContext.Current.Server.MapPath(xmlFilePath);
            string path = xmlFilePath;
            MemoryStream ms = null;
            XmlTextWriter XmlWt = null;
            try
            {
                ms = new MemoryStream();
                //根据ms实例化XmlWt
                XmlWt = new XmlTextWriter(ms, Encoding.Unicode);
                //获取ds中的数据
                dt.WriteXml(XmlWt);
                int count = (int)ms.Length;
                byte[] temp = new byte[count];
                ms.Seek(0, SeekOrigin.Begin);
                ms.Read(temp, 0, count);
                //返回Unicode编码的文本
                UnicodeEncoding ucode = new UnicodeEncoding();
                //写文件
                StreamWriter sw = new StreamWriter(path);