试一试xmltextwriter
XmlTextWriter xtw=new XmlTextWriter("c:\\1.xml",null);
xtw.WriteStartDocument();
xtw.WriteStartElement("DataSet");
xtw.WriteStartElement("DB");
xtw.WriteElementString("a","aaaaa");
xtw.WriteElementString("b","bbbbb");
xtw.WriteEndElement(); xtw.WriteStartElement("DB");
xtw.WriteElementString("a","aaaa1");
xtw.WriteElementString("b","bbbb1");
xtw.WriteEndElement();
xtw.WriteEndElement();
xtw.WriteEndDocument();
xtw.Flush();
xtw.Close();
XmlTextWriter xtw=new XmlTextWriter("c:\\1.xml",null);
xtw.WriteStartDocument();
xtw.WriteStartElement("DataSet");
xtw.WriteStartElement("DB");
xtw.WriteElementString("a","aaaaa");
xtw.WriteElementString("b","bbbbb");
xtw.WriteEndElement(); xtw.WriteStartElement("DB");
xtw.WriteElementString("a","aaaa1");
xtw.WriteElementString("b","bbbb1");
xtw.WriteEndElement();
xtw.WriteEndElement();
xtw.WriteEndDocument();
xtw.Flush();
xtw.Close();
System.XML.Attribute attr;
xdd.Load("<CustomerInfo/>");
attr=xdd.CreateAttribute("订单ID");
attr.Value=变量值;
xdd.DocumentElement.Attributes.Append(attr);
attr=xdd.CreateAttribute("客户ID");
attr.Value=变量值;
xdd.DocumentElement.Attributes.Append(attr);
……
xdd.Save("CustomerInfo.xml");