C#读写XML

XML结构：

<?xml version="1.0" encoding="utf-8" ?> 
- <bookstore>
 - <book>
    <title>C# premier</title> 
    <price>$15.0</price> 
   </book>
  </bookstore>

前台主要代码：

 <asp:GridView ID="gvBook" runat="server" AutoGenerateColumns="False">
  <Columns>
  <asp:BoundField DataField="title" HeaderText="书名" />
  <asp:BoundField DataField="price" HeaderText="价格" />
  </Columns>
  </asp:GridView>
  <br />
  书名：<asp:TextBox ID="tbTitle" runat="server"></asp:TextBox>
  <br />
  价格：<asp:TextBox ID="tbPrice" runat="server" ></asp:TextBox><br />
  <asp:Button ID="btnAdd" runat="server" Text="添加" OnClick="btnAdd_Click" />

后台主要代码：

protected void Page_Load(object sender, EventArgs e)
  {
  if (!IsPostBack)
  {
  ReadXML();
  }
  }

  /// <summary>
  /// 读XML
  /// </summary>
  public void ReadXML()
  {
  StreamReader sr = new StreamReader(Server.MapPath("xmlFile.xml"));

  XmlDataDocument xdd = new XmlDataDocument();
  xdd.DataSet.ReadXml(sr);

  gvBook.DataSource = xdd.DataSet.Tables[0].DefaultView;
  gvBook.DataBind();

  sr.Close();
  }
   
  /// <summary>
  /// 写XML
  /// </summary>
  public void WriteXML()
  {
  string title = tbTitle.Text;
  string price = tbPrice.Text;
  string xmlPath=Server.MapPath("xmlFile.xml");

  XmlDocument xd = new XmlDocument();
  xd.Load(xmlPath);

  //构建根结点的子结点
  XmlElement xe1=xd.CreateElement("title");
  XmlText xt1=xd.CreateTextNode(title);
  XmlElement xe2=xd.CreateElement("price");
  XmlText xt2 = xd.CreateTextNode(price);
  XmlNode xe=xd.CreateNode("element","book","");
  xe.AppendChild(xe1);
  xe.LastChild.AppendChild(xt1);
  xe.AppendChild(xe2);
  xe.LastChild.AppendChild(xt2);

  //在根结点下追加一下新结点
  XmlElement root = xd.DocumentElement;
  root.AppendChild(xe);
  xd.Save(xmlPath);  
  }

  //向XML中添加记录
  protected void btnAdd_Click(object sender, EventArgs e)
  {
    WriteXML();
    ReadXML();
  }