public static XmlDocument getDoc(String path)//加载xml文档
{
  XmlDocument doc = new XmlDocument();
  doc.Load(path);
  return doc;
} 
/// <summary>
/// 返回找到的节点下标
/// </summary>
/// <param name="path">xml文件路径</param>
/// <param name="bname">书名</param>
/// <returns></returns>
public static int getPosition(String path,string node, String bname)
{
  int i;
  XmlDocument doc = new XmlDocument();
  doc.Load(path);
  XmlNodeList nodeList = doc.SelectSingleNode(node).ChildNodes;
  for (i = 0; i < nodeList.Count; i++)
  {
 if (nodeList[i].ChildNodes[0].InnerText == bname)
 {
   return i;
 }
  }
  return -1;
}

/// <summary>
/// 遍历数据
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void btnRead_Click(object sender, EventArgs e)
{

  XmlDocument doc = getDoc("books.xml");//加载xml文档，books文件存放于
  foreach (XmlElement root in doc.DocumentElement.ChildNodes)//遍历根的子节点
  {
 Response.Write("<script>document.write('<br/>');</script>");
 Response.Write("<script>document.write('" + root.Name + "');</script>");//节点名root.Name book
 foreach (XmlElement item in root.ChildNodes)
 {
   Response.Write("<script>document.write('" + item.Name + "'+':'+'" + item.InnerText + "');</script>");//输出节点名和文本节点的值
   Response.Write("<script>document.write('<br/>');</script>");
 }
  }
}

/// <summary>
/// 查找
/// </summary>
/// <param name="path">文件路径</param>
/// <param name="node">节点</param>
/// <param name="bname">查找关键字</param>
/// <returns>XmlNode</returns>
public static XmlNode Find(string path,string node,string bname)
{
  XmlDocument doc = new XmlDocument();
  doc.Load(path);//加载xml文档
  XmlNodeList nodeList = doc.SelectSingleNode(node).ChildNodes;
  int i = getPosition(path, node, bname);//
  if (i >= 0)
 return nodeList[i];
  else
 return null;
}

/// <summary>
/// 删除元素、属性
/// </summary>
/// <param name="path">文件</param>
/// <param name="node">指定节点的父节点</param>
/// <param name="attribute">为空时删除节点，否则删除属性</param>
/// <param name="bname"></param>
public static void Delete(string path,string node,string attribute,string bname)
{
  XmlDocument doc = new XmlDocument();
  doc.Load(path);
  XmlNode root = doc.SelectSingleNode(node);
  XmlNodeList nodeList = doc.SelectSingleNode(node).ChildNodes;
  int i = getPosition(path, node, bname);//返回指定的节点下标
  if (i >= 0)
  {
 if (attribute.Equals(""))
 {
   root.RemoveChild(nodeList[i]);
 }
 else
 {
   XmlElement xn = (XmlElement)nodeList[i];
   xn.RemoveAttribute(attribute);
 }
  }
  doc.Save(path);
}

/// <summary>
/// 添加元素值
/// </summary>
/// <param name="path"></param>
/// <param name="node"></param>
/// <param name="element"></param>
/// <param name="value"></param>
/// <param name="i">插入的下标，如果为负，默认从最后一个节点插入</param>
/// <returns></returns>
public static bool Add(string path,string node,string element,string value,int i)
{
  XmlDocument doc = new XmlDocument();
  doc.Load(path);
  XmlNodeList nodeList = doc.SelectNodes(node);
  XmlNode newNode = doc.SelectSingleNode(node).LastChild;
  if (i < 0 || i > nodeList.Count-1)//如果小于0或者大于节点长度，默认从最后一个节点添加
  {
 XmlElement newElement = doc.CreateElement(element);//创建元素
 newElement.InnerText = value;//赋值
 newNode.AppendChild(newElement);
  }
  else
  {
 XmlElement newElement = doc.CreateElement(element);
 newElement.InnerText = value;
 nodeList[i - 1].AppendChild(newElement);
  }
  doc.Save(path);
  return true;
}