XML 增、删、改和查示例

1.已知有一个XML文件（bookstore.xml）如下：

<?xml version="1.0" encoding="gb2312"?>
<bookstore>
<book genre="fantasy" ISBN="2-3631-4">
    <title>Oberon's Legacy</title>
    <author>Corets, Eva</author>
    <price>5.95</price>
</book>
</bookstore>

1、往<bookstore>节点中插入一个<book>节点：

   XmlDocument xmlDoc=new XmlDocument();
   xmlDoc.Load("bookstore.xml");
   XmlNode root=xmlDoc.SelectSingleNode("bookstore");//查找<bookstore>
   XmlElement xe1=xmlDoc.CreateElement("book");//创建一个<book>节点
   xe1.SetAttribute("genre","李赞红");//设置该节点genre属性
   xe1.SetAttribute("ISBN","2-3631-4");//设置该节点ISBN属性

   XmlElement xesub1=xmlDoc.CreateElement("title");
   xesub1.InnerText="CS从入门到精通";//设置文本节点
   xe1.AppendChild(xesub1);//添加到<book>节点中
   XmlElement xesub2=xmlDoc.CreateElement("author");
   xesub2.InnerText="候捷";
   xe1.AppendChild(xesub2);
   XmlElement xesub3=xmlDoc.CreateElement("price");
   xesub3.InnerText="58.3";
   xe1.AppendChild(xesub3);

   root.AppendChild(xe1);//添加到<bookstore>节点中
   xmlDoc.Save("bookstore.xml");

//================
结果为：

<?xml version="1.0" encoding="gb2312"?>
<bookstore>
<book genre="fantasy" ISBN="2-3631-4">
    <title>Oberon's Legacy</title>
    <author>Corets, Eva</author>
    <price>5.95</price>
</book>
<book genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
</book>
</bookstore>

2、修改节点：将genre属性值为“李赞红“的节点的genre值改为“update李赞红”，将该节点的子节点<author>的文本修改为“亚胜”。

    XmlNodeList nodeList=xmlDoc.SelectSingleNode("bookstore").ChildNodes;//获取bookstore节点的所有子节点
   foreach(XmlNode xn in nodeList)//遍历所有子节点
   {
    XmlElement xe=(XmlElement)xn;//将子节点类型转换为XmlElement类型
    if(xe.GetAttribute("genre")=="李赞红")//如果genre属性值为“李赞红”
    {
     xe.SetAttribute("genre","update李赞红");//则修改该属性为“update李赞红”

     XmlNodeList nls=xe.ChildNodes;//继续获取xe子节点的所有子节点
     foreach(XmlNode xn1 in nls)//遍历
     {
      XmlElement xe2=(XmlElement)xn1;//转换类型
      if(xe2.Name=="author")//如果找到
      {
       xe2.InnerText="亚胜";//则修改
       break;//找到退出来就可以了
      }
     }
     break;
    }
   }

   xmlDoc.Save("bookstore.xml");//保存。

//=================

最后结果为：

<?xml version="1.0" encoding="gb2312"?>
<bookstore>
<book genre="fantasy" ISBN="2-3631-4">
    <title>Oberon's Legacy</title>
    <author>Corets, Eva</author>
    <price>5.95</price>
</book>
<book genre="update李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>亚胜</author>
    <price>58.3</price>
</book>
</bookstore>

3、删除 <book genre="fantasy" ISBN="2-3631-4">节点的genre属性，删除 <book genre="update李赞红" ISBN="2-3631-4">节点。

XmlNodeList xnl=xmlDoc.SelectSingleNode("bookstore").ChildNodes;

   foreach(XmlNode xn in xnl)
   {
    XmlElement xe=(XmlElement)xn;

    if(xe.GetAttribute("genre")=="fantasy")
    {
     xe.RemoveAttribute("genre");//删除genre属性
    }
    else if(xe.GetAttribute("genre")=="update李赞红")
    {
     xe.RemoveAll();//删除该节点的全部内容
    }
   }
   xmlDoc.Save("bookstore.xml");

//====================

最后结果为：

<?xml version="1.0" encoding="gb2312"?>
<bookstore>
<book ISBN="2-3631-4">
    <title>Oberon's Legacy</title>
    <author>Corets, Eva</author>
    <price>5.95</price>
</book>
<book>
</book>
</bookstore>

4、显示所有数据。

XmlNode xn=xmlDoc.SelectSingleNode("bookstore");

   XmlNodeList xnl=xn.ChildNodes;

   foreach(XmlNode xnf in xnl)
   {
    XmlElement xe=(XmlElement)xnf;
    Console.WriteLine(xe.GetAttribute("genre"));//显示属性值
    Console.WriteLine(xe.GetAttribute("ISBN"));

    XmlNodeList xnf1=xe.ChildNodes;
    foreach(XmlNode xn2 in xnf1)
    {
     Console.WriteLine(xn2.InnerText);//显示子节点点文本
    }
   }

留做参考,原文地址http://blog.yesky.com/75/richsee/1211075.shtml

2前台代码：html

<%@ Page language="c#" Codebehind="Main.aspx.cs" AutoEventWireup="false" Inherits="DsAndXML.OpXMLFile.Main" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >

<HTML>

<HEAD>

</HEAD>

<asp:DataGrid id="dgShow" style="Z-INDEX: 100; LEFT: 113px; POSITION: absolute; TOP: 32px" runat="server" Width="480px" Height="178px"></asp:DataGrid>

<asp:Label id="Label3" style="Z-INDEX: 111; LEFT: 187px; POSITION: absolute; TOP: 383px" runat="server" Width="120px" Height="21px">新邮件地址：</asp:Label>

<asp:Label id="Label2" style="Z-INDEX: 107; LEFT: 333px; POSITION: absolute; TOP: 274px" runat="server" Width="83px" Height="21px">邮件地址：</asp:Label>

<asp:Button id="btnAdd" style="Z-INDEX: 104; LEFT: 298px; POSITION: absolute; TOP: 324px" runat="server" Text="添加"></asp:Button>

<asp:Button id="btnDelete" style="Z-INDEX: 103; LEFT: 199px; POSITION: absolute; TOP: 324px" runat="server" Text="删除"></asp:Button>

<asp:Button id="btnChange" style="Z-INDEX: 102; LEFT: 102px; POSITION: absolute; TOP: 382px" runat="server" Text="修改"></asp:Button>

<asp:Button id="btnQuery" style="Z-INDEX: 101; LEFT: 101px; POSITION: absolute; TOP: 324px" runat="server" Text="查询"></asp:Button>

<asp:DropDownList id="ddlName" style="Z-INDEX: 105; LEFT: 210px; POSITION: absolute; TOP: 274px" runat="server" Width="95px" Height="78px"></asp:DropDownList>

<asp:Label id="Label1" style="Z-INDEX: 106; LEFT: 100px; POSITION: absolute; TOP: 274px" runat="server" Width="83px" Height="21px">姓名：</asp:Label>

<asp:Label id="lbEmail" style="Z-INDEX: 109; LEFT: 459px; POSITION: absolute; TOP: 274px" runat="server" Width="231px"></asp:Label>

<asp:TextBox id="tbNewMail" style="Z-INDEX: 110; LEFT: 330px; POSITION: absolute; TOP: 381px" runat="server" Width="208px" Height="26px"></asp:TextBox></FONT>

</form>

</body>

</HTML>

XML文件dbGuest.xml

<?xml version="1.0" standalone="yes"?>

<User>

<City>shanghai</City>

</User>

<User>

<Name>shaoazhd</Name>

<City>beijing</City>

</User>

<User>

<Name>Guset</Name>

</User>

<User>

<Name>Guset</Name>

</User>

</dbGuest>

using System;

using System.Collections;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Web;

using System.Web.SessionState;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.HtmlControls;

using System.Xml;

using System.Xml.XPath;

namespace DsAndXML.OpXMLFile

{

/// <summary>

/// Main 的摘要说明。

/// </summary>

public class Main : System.Web.UI.Page

{

protected System.Web.UI.WebControls.Button btnQuery;

protected System.Web.UI.WebControls.Button btnChange;

protected System.Web.UI.WebControls.Button btnDelete;

protected System.Web.UI.WebControls.Button btnAdd;

protected System.Web.UI.WebControls.DropDownList ddlName;

protected System.Web.UI.WebControls.Label Label1;

protected System.Web.UI.WebControls.Label Label2;

protected System.Web.UI.WebControls.Label lbEmail;

protected System.Web.UI.WebControls.TextBox tbNewMail;

protected System.Web.UI.WebControls.Label Label3;

protected System.Web.UI.WebControls.DataGrid dgShow;

private void Page_Load(object sender, System.EventArgs e)

{

// 在此处放置用户代码以初始化页面

if(!IsPostBack)

Bind();

}

private void Bind()

{

DataSet ds = new DataSet();

ds.ReadXml(Server.MapPath(".\\db\\dbGuest.xml"));

dgShow.DataSource = ds.Tables[0].DefaultView;

dgShow.DataBind();

XmlDocument doc = new XmlDocument();

doc.Load(Server.MapPath(".\\db\\dbGuest.xml"));

XmlNodeList elemList = doc.GetElementsByTagName("Name");

ddlName.Items.Clear();

for(int i=0;i<elemList.Count;i++)

ddlName.Items.Add(elemList[i].InnerXml);

}

Web Form Designer generated code

private void btnQuery_Click(object sender, System.EventArgs e)

{

XmlDocument doc = new XmlDocument();

doc.Load(Server.MapPath(".\\db\\dbGuest.xml"));

lbEmail.Text = doc.SelectSingleNode("//User[Name='"+ddlName.SelectedItem.Text+"']").ChildNodes.Item(2).InnerText;

}

private void btnChange_Click(object sender, System.EventArgs e)

{

XmlDocument xmlDoc = new XmlDocument();

xmlDoc.Load(Server.MapPath(".\\db\\dbGuest.xml"));

XmlNodeList nodeList=xmlDoc.SelectSingleNode("dbGuest").ChildNodes;//获取dbGuest节点的所有子节点

foreach(XmlNode xn in nodeList)//遍历所有子节点

{

XmlElement xe=(XmlElement)xn;//将子节点类型转换为XmlElement类型

XmlNodeList node = xe.GetElementsByTagName("Name");

if(node.Count>0)

{

if(node[0].InnerText==ddlName.SelectedItem.Text)

{

XmlNodeList nls=xe.ChildNodes;//继续获取xe子节点的所有子节点

foreach(XmlNode xn1 in nls)//遍历

{

XmlElement xe2=(XmlElement)xn1;//转换类型

if(xe2.Name=="Email")//如果找到

{

xe2.InnerText=tbNewMail.Text;//则修改

break;//找到退出来就可以了

}

break;

}

xmlDoc.Save(Server.MapPath(".\\db\\dbGuest.xml"));

Bind();

}

private void btnDelete_Click(object sender, System.EventArgs e)

{

XmlDocument xmlDoc = new XmlDocument();

xmlDoc.Load(Server.MapPath(".\\db\\dbGuest.xml"));

XmlNodeList xnl=xmlDoc.SelectSingleNode("dbGuest").ChildNodes;

foreach(XmlNode xn in xnl)

{

XmlElement xe=(XmlElement)xn;

XmlNodeList node = xe.GetElementsByTagName("Name");

if(node.Count>0)

{

if(node[0].InnerText==ddlName.SelectedItem.Text)

xe.RemoveAll();//删除该节点的全部内容

break;

}

xmlDoc.Save(Server.MapPath(".\\db\\dbGuest.xml"));

Bind();

}

private void btnAdd_Click(object sender, System.EventArgs e)

{

XmlDocument xmlDoc = new XmlDocument();

xmlDoc.Load(Server.MapPath(".\\db\\dbGuest.xml"));

XmlNode root=xmlDoc.SelectSingleNode("dbGuest");//查找<dbGuest>

XmlElement xe1=xmlDoc.CreateElement("User");//创建一个<User>节点

XmlElement xesub1=xmlDoc.CreateElement("Name");

xesub1.InnerText="Guset";//设置文本节点

xe1.AppendChild(xesub1);//添加到<User>节点中

XmlElement xesub2=xmlDoc.CreateElement("City");

xesub2.InnerText="上海";

xe1.AppendChild(xesub2);

XmlElement xesub3=xmlDoc.CreateElement("Email");

xesub3.InnerText="ss@22.net";

xe1.AppendChild(xesub3);

root.AppendChild(xe1);//添加到<dbGuest>节点中

xmlDoc.Save(Server.MapPath(".\\db\\dbGuest.xml"));

Bind();

}

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原文地址：https://www.cnblogs.com/ghd258/p/254218.html