asp.net操作xml（增删查改）

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asp.net操作xml

1.xml文档Products.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <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">
 3   <item belong="数码">
 4     <id>1</id>
 5     <name>手机</name>
 6     <price>1000</price>
 7   </item>
 8   <item belong="服装">
 9     <id>2</id>
10     <name>男装</name>
11     <price>200</price>
12   </item>
13   <item belong="食品">
14     <id>3</id>
15     <name>黄瓜</name>
16     <price>4</price>
17   </item>
18 </products>

2.schema约束文档 products.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <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">
 3   <element name="products" type="pro:pro"></element>
 4   <complexType name="pro">
 5     <sequence>
 6       <element name="item" maxOccurs="unbounded">
 7         <complexType>
 8           <sequence>
 9             <element name="id" type="string"></element>
10             <element name="name" type="string"></element>
11             <element name="price">
12               <simpleType>
13                 <restriction base="float">
14                   <maxExclusive value="10000"></maxExclusive>
15                   <minInclusive value="0"></minInclusive>
16                 </restriction>
17               </simpleType>
18             </element>
19           </sequence>
20           <attribute name="belong" type="string"></attribute>
21         </complexType>
22       </element>
23     </sequence>
24   </complexType>
25 </schema>

3.定义实体类 DBPro.cs

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Web;
 5 
 6 /// <summary>
 7 ///DBPro 的摘要说明
 8 /// </summary>
 9 public class DBPro
10 {
11     string belong;
12     string id;
13     string name;
14     string price;
15     public DBPro(string belong,string id,string name,string price)
16     {
17         this.belong = belong;
18         this.id = id;
19         this.name = name;
20         this.price = price;
21     }
22     public string Belong
23     {
24         get { return belong; }
25         set { belong = value; }
26     }
27     public string ID
28     {
29         get { return id; }
30         set { id = value; }
31     }
32     public string Name
33     {
34         get { return name; }
35         set{name=value;}
36     }
37     public string Price
38     {
39         get { return price; }
40         set { price = value; }
41     }
42 }

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

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Web;
  5 using System.Web.UI;
  6 using System.Web.UI.WebControls;
  7 using System.Xml;
  8 
  9 public partial class _Default : System.Web.UI.Page
 10 {
 11     protected void Page_Load(object sender, EventArgs e)
 12     {   //选择方法进行测试
 13         //SearchXml();
 14         DBPro pro = new DBPro("家电","10", "电视", "3999");
 15         AddToXml(pro);
 16         //UpdateOneXml(pro);
 17         //DeleteXml("10");
 18     }
 19     /// <summary>
 20     /// 遍历xml文档
 21     /// </summary>
 22     /// <param name="pro"></param>
 23     private void SearchXml()
 24     {
 25         //提取xml文档
 26         XmlDocument xd = new XmlDocument();
 27         xd.Load(System.Web.HttpContext.Current.Server.MapPath("Products.xml"));
 28         //获取根节点
 29         XmlNode root = xd.DocumentElement;
 30         //获取节点列表
 31         XmlNodeList items = root.ChildNodes;
 32         //遍历item项
 33         Response.Write("<pre>");
 34         foreach (XmlNode item in items)
 35         {
 36          //输出属性
 37             Response.Write(item.Attributes["belong"].Name + "=" + item.Attributes["belong"].InnerText);
 38             //遍历输出子节点
 39             foreach (XmlNode p in item)
 40             {
 41                 Response.Write(p.Name + "=" + p.InnerText);
 42             }
 43         }
 44         Response.Write("</pre>");
 45     }
 46     /// <summary>
 47     /// xml添加
 48     /// </summary>
 49     /// <param name="pro"></param>
 50     private void AddToXml(DBPro pro)
 51     {
 52         //提取xml文档
 53         XmlDocument xd = new XmlDocument();
 54         xd.Load(System.Web.HttpContext.Current.Server.MapPath("Products.xml"));
 55         //获取根节点
 56         XmlNode root = xd.DocumentElement;
 57         //创建元素
 58         XmlElement newItem = xd.CreateElement("item");
 59         XmlElement newID = xd.CreateElement("id");
 60         XmlElement newName = xd.CreateElement("name");
 61         XmlElement newPrice = xd.CreateElement("price");
 62         //配置参数
 63         newItem.SetAttribute("belong", pro.Belong);
 64         newID.InnerText = pro.ID;
 65         newName.InnerText = pro.Name;
 66         newPrice.InnerText = pro.Price;
 67         //装配
 68         root.AppendChild(newItem);
 69         newItem.AppendChild(newID);
 70         newItem.AppendChild(newName);
 71         newItem.AppendChild(newPrice);
 72         xd.Save(System.Web.HttpContext.Current.Server.MapPath("Products.xml"));
 73     }
 74     /// <summary>
 75     /// 修改xml一项
 76     /// </summary>
 77     /// <param name="pro"></param>
 78     private void UpdateOneXml(DBPro pro)
 79     {
 80         //提取xml文档
 81         XmlDocument xd = new XmlDocument();
 82         xd.Load(System.Web.HttpContext.Current.Server.MapPath("Products.xml"));
 83         //获取根节点
 84         XmlNode root = xd.DocumentElement;
 85         //获取节点列表
 86         XmlNodeList items = root.ChildNodes;
 87         //遍历节点列表
 88         foreach (XmlNode item in items)
 89         {
 90             //遍历item
 91             foreach (XmlNode p in item)
 92             {
 93                 if (p.Name == "id" && p.InnerText == pro.ID)
 94                 {
 95                     item.Attributes["belong"].InnerText = pro.Belong;
 96                     p.NextSibling.InnerText = pro.Name;
 97                     p.NextSibling.NextSibling.InnerText = pro.Price;
 98                 }
 99             }
100         }
101     }
102     /// <summary>
103     /// 删除xml一项
104     /// </summary>
105     /// <param name="pro"></param>
106     private void DeleteXml(string id)
107     {
108          //提取xml文档
109         XmlDocument xd = new XmlDocument();
110         xd.Load(System.Web.HttpContext.Current.Server.MapPath("Products.xml"));
111         //获取根节点
112         XmlNode root = xd.DocumentElement;
113         //获取节点列表
114         XmlNodeList items = root.ChildNodes;
115         //遍历节点列表
116         foreach (XmlNode item in items)
117         {
118             //遍历item
119             foreach (XmlNode p in item)
120             {
121                 if (p.Name == "id" && p.InnerText == id)
122                 {
123                     root.RemoveChild(item);
124                 }
125             }
126         }
127     }
128 }

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！