asp.net操作xml（增删查改）

asp.net操作xml

1.xml文档Products.xml

<?xml version="1.0" encoding="utf-8"?>
<products xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.pro.org/2001/products" xsi:schemaLocation="http://www.pro.org/2001/products products.xsd">
  <item belong="数码">
    <id>1</id>
    <name>手机</name>
    <price>1000</price>
  </item>
  <item belong="服装">
    <id>2</id>
    <name>男装</name>
    <price>200</price>
  </item>
  <item belong="食品">
    <id>3</id>
    <name>黄瓜</name>
    <price>4</price>
  </item>
</products>

 2.schema约束文档 products.xml

<?xml version="1.0" encoding="utf-8"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.pro.org/2001/products" xmlns:pro="http://www.pro.org/2001/products" elementFormDefault="qualified">
  <element name="products" type="pro:pro"></element>
  <complexType name="pro">
    <sequence>
      <element name="item" maxOccurs="unbounded">
        <complexType>
          <sequence>
            <element name="id" type="string"></element>
            <element name="name" type="string"></element>
            <element name="price">
              <simpleType>
                <restriction base="float">
                  <maxExclusive value="10000"></maxExclusive>
                  <minInclusive value="0"></minInclusive>
                </restriction>
              </simpleType>
            </element>
          </sequence>
          <attribute name="belong" type="string"></attribute>
        </complexType>
      </element>
    </sequence>
  </complexType>
</schema>

3.定义实体类 DBPro.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

/// <summary>
///DBPro 的摘要说明
/// </summary>
public class DBPro
{
    string belong;
    string id;
    string name;
    string price;
    public DBPro(string belong,string id,string name,string price)
    {
        this.belong = belong;
        this.id = id;
        this.name = name;
        this.price = price;
    }
    public string Belong
    {
        get { return belong; }
        set { belong = value; }
    }
    public string ID
    {
        get { return id; }
        set { id = value; }
    }
    public string Name
    {
        get { return name; }
        set{name=value;}
    }
    public string Price
    {
        get { return price; }
        set { price = value; }
    }
}

4.新建一个web窗体Defaut.aspx，在Default.aspx.cs中编写核心代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {   //选择方法进行测试
        //SearchXml();
        DBPro pro = new DBPro("家电","10", "电视", "3999");
        AddToXml(pro);
        //UpdateOneXml(pro);
        //DeleteXml("10");
    }
    /// <summary>
    /// 遍历xml文档
    /// </summary>
    /// <param name="pro"></param>
    private void SearchXml()
    {
        //提取xml文档
        XmlDocument xd = new XmlDocument();
        xd.Load(System.Web.HttpContext.Current.Server.MapPath("Products.xml"));
        //获取根节点
        XmlNode root = xd.DocumentElement;
        //获取节点列表
        XmlNodeList items = root.ChildNodes;
        //遍历item项
        Response.Write("<pre>");
        foreach (XmlNode item in items)
        {
         //输出属性
            Response.Write(item.Attributes["belong"].Name + "=" + item.Attributes["belong"].InnerText);
            //遍历输出子节点
            foreach (XmlNode p in item)
            {
                Response.Write(p.Name + "=" + p.InnerText);
            }
        }
        Response.Write("</pre>");
    }
    /// <summary>
    /// xml添加
    /// </summary>
    /// <param name="pro"></param>
    private void AddToXml(DBPro pro)
    {
        //提取xml文档
        XmlDocument xd = new XmlDocument();
        xd.Load(System.Web.HttpContext.Current.Server.MapPath("Products.xml"));
        //获取根节点
        XmlNode root = xd.DocumentElement;
        //创建元素
        XmlElement newItem = xd.CreateElement("item");
        XmlElement newID = xd.CreateElement("id");
        XmlElement newName = xd.CreateElement("name");
        XmlElement newPrice = xd.CreateElement("price");
        //配置参数
        newItem.SetAttribute("belong", pro.Belong);
        newID.InnerText = pro.ID;
        newName.InnerText = pro.Name;
        newPrice.InnerText = pro.Price;
        //装配
        root.AppendChild(newItem);
        newItem.AppendChild(newID);
        newItem.AppendChild(newName);
        newItem.AppendChild(newPrice);
        xd.Save(System.Web.HttpContext.Current.Server.MapPath("Products.xml"));
    }
    /// <summary>
    /// 修改xml一项
    /// </summary>
    /// <param name="pro"></param>
    private void UpdateOneXml(DBPro pro)
    {
        //提取xml文档
        XmlDocument xd = new XmlDocument();
        xd.Load(System.Web.HttpContext.Current.Server.MapPath("Products.xml"));
        //获取根节点
        XmlNode root = xd.DocumentElement;
        //获取节点列表
        XmlNodeList items = root.ChildNodes;
        //遍历节点列表
        foreach (XmlNode item in items)
        {
            //遍历item
            foreach (XmlNode p in item)
            {
                if (p.Name == "id" && p.InnerText == pro.ID)
                {
                    item.Attributes["belong"].InnerText = pro.Belong;
                    p.NextSibling.InnerText = pro.Name;
                    p.NextSibling.NextSibling.InnerText = pro.Price;
                }
            }
        }
    }
    /// <summary>
    /// 删除xml一项
    /// </summary>
    /// <param name="pro"></param>
    private void DeleteXml(string id)
    {
         //提取xml文档
        XmlDocument xd = new XmlDocument();
        xd.Load(System.Web.HttpContext.Current.Server.MapPath("Products.xml"));
        //获取根节点
        XmlNode root = xd.DocumentElement;
        //获取节点列表
        XmlNodeList items = root.ChildNodes;
        //遍历节点列表
        foreach (XmlNode item in items)
        {
            //遍历item
            foreach (XmlNode p in item)
            {
                if (p.Name == "id" && p.InnerText == id)
                {
                    root.RemoveChild(item);
                }
            }
        }
    }
}

此处应注意：用XMLDocument添加元素，遇到了这样一个问题：
当根节点具有 xmlns 属性时，用 XMLDocument 创建子元素时如果不指定 xmlns 或指定 xmlns 为 null 时，子元素将自动具有 xmlns="" 属性

<item belong="家电" xmlns="">
    <id>10</id>
    <name>电视</name>
    <price>3999</price>
  </item>
问题原因：

    当父节点具有 xmlns 属性时，子节点必须指定 xmlns 属性，仅当子节点的 xmnls 属性与父节点相同时，子节点才不显示 xmlns 属性，最终就不会在 .xml 文件中显示出来

解决办法:

        XmlElement newItem = xd.CreateElement("item",xd.DocumentElement.NamespaceURI);
        XmlElement newID = xd.CreateElement("id",xd.DocumentElement.NamespaceURI);
        XmlElement newName = xd.CreateElement("name",xd.DocumentElement.NamespaceURI);
        XmlElement newNumber = xd.CreateElement("number",xd.DocumentElement.NamespaceURI);

        在每一个下级节点，都要继续指定命名空间，否则仍会出现 xmlns="" 属性。

///新手上道，若有不足或错误之处，敬请各位大神批评指正！