OperateXMLDateSet

protected void btnRead_Click(object sender, EventArgs e)
{
   DataSet ds = new DataSet();
   ds.ReadXml(Server.MapPath("Employee.xml"));//读取XML文件
   //GridView控件配置数据源
   gvEmployee.DataSource = ds;
   gvEmployee.DataBind();

}
protected void btnWrite_Click(object sender, EventArgs e)
{
   //创建DataTable
   DataTable dt = new DataTable("Employee");
   //创建DataColumn
   DataColumn dcID = new DataColumn("ID", typeof(string));
   DataColumn dcNAME = new DataColumn("NAME", typeof(string));
   DataColumn dcAGE = new DataColumn("AGE", typeof(string));
   DataColumn dcDEPT = new DataColumn("DEPT", typeof(string));
   dt.Columns.AddRange(new DataColumn[] { dcID, dcNAME, dcAGE, dcDEPT });
   //创建DataRow
   DataRow dr = dt.NewRow();
   dr["ID"] = "MR0004";
   dr["NAME"] = "小李";
   dr["AGE"] = "29";
   dr["DEPT"] = "项目策划";
   dt.Rows.Add(dr);
   //创建一个DataSet
   DataSet ds2 = new DataSet();
   ds2.Tables.Add(dt);
   //读取原有的XML数据
   DataSet ds = new DataSet();
   ds.ReadXml(Server.MapPath("Employee.xml"));
   //合并两个DataSet
   ds.Merge(ds2);
   ds.WriteXml(Server.MapPath("Employee.xml"));
   Page.ClientScript.RegisterStartupScript(GetType(), "", "alert('写入成功！');", true);

   }

Employee.xml

<NewDataSet>
   <Employee>
      <ID>MR0001</ID>
      <NAME>小王</NAME>
      <AGE>27</AGE>
      <DEPT>软件开发</DEPT>
   </Employee>
   <Employee>
      <ID>MR0004</ID>
      <NAME>小李</NAME>
      <AGE>29</AGE>
      <DEPT>项目策划</DEPT>
   </Employee>
</NewDataSet>