讀寫xml文件
已知有一個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>節點中插入一個<book>節,實現代碼如下:

? protected void btnAddXml_Click(object sender, System.EventArgs e)
??? ...{
?????? XmlDocument xmlDoc = new XmlDocument();
?????? xmlDoc.Load(Server.MapPath("bookstore.xml"));?
?????? XmlNode root = xmlDoc.SelectSingleNode("bookstore"); //查找<bookstore>
?????? XmlElement xe1=xmlDoc.CreateElement("book");//創建一個<book>節點
?????? xe1.SetAttribute("genre","李贊紅");//設置該節點genre屬性
?????? xe1.SetAttribute("ISBN","2-3631-4");//設置該節點ISBN屬性
?????? XmlElement xesub1=xmlDoc.CreateElement("title");
?????? xesub1.InnerText="CS從入門到精通";//設置文本節點
?????? xe1.AppendChild(xesub1);//添加到<book>節點中
?????? 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>節點中
?????? xmlDoc.Save(Server.MapPath("bookstore.xml"));
??? }
添加節點后的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>
? <book genre="李贊紅" ISBN="2-3631-4">
??? <title>CS從入門到精通</title>
??? <author>候捷</author>
??? <price>58.3</price>
? </book>
</bookstore>2、修改節點：將genre屬性值為“李贊紅“的節點的genre值改為“update李贊紅”，將該節點的子節點<author>的文本修改為“亞勝”。
?

protected void btnUpdateXml_Click(object sender, System.EventArgs e)
??? ...{
?????? XmlDocument xmlDoc = new XmlDocument();
?????? xmlDoc.Load(Server.MapPath("bookstore.xml"));
?????? XmlNodeList nodeList = xmlDoc.SelectSingleNode("bookstore").ChildNodes;//獲取bookstore節點的所有子節點
?????? foreach(XmlNode xn in nodeList)//遍歷所有子節點
?????? ...{??? XmlElement xe=(XmlElement)xn;//將子節點類型轉換為XmlElement類型???
??????????? if(xe.GetAttribute("genre")=="李贊紅")//如果genre屬性值為“李贊紅”????
??????????? ...{????????
??????????????? xe.SetAttribute("genre","update李贊紅");//則修改該屬性為“update李贊紅”????????
??????????????? XmlNodeList nls=xe.ChildNodes;//繼續獲取xe子節點的所有子節點?????????
??????????????? foreach(XmlNode xn1 in nls)//遍歷?????????
??????????????? ...{??????????????
??????????????????? XmlElement xe2=(XmlElement)xn1;//轉換類型??????????????
??????????????????? if(xe2.Name=="author")//如果找到??????????????
??????????????????? ...{???????????????????
??????????????????????? xe2.InnerText="亞勝";//則修改???????????????????
??????????????????????? break;//找到退出來就可以了??????????????
??????????????????? }?????????
??????????????? }?????????
??????????????? break;???
??????????? }
?????? }
??????? xmlDoc.Save(Server.MapPath("bookstore.xml"));//保存
??? }
修改后的結果為:

<?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李贊紅" ISBN="2-3631-4">
??? <title>CS從入門到精通</title>
??? <author>亞勝</author>
??? <price>58.3</price>
? </book>
</bookstore>3、刪除 <book genre="fantasy" ISBN="2-3631-4">節點的genre屬性，刪除 <book genre="update李贊紅" ISBN="2-3631-4">節點。 protected void btnDeleteXml_Click(object sender, System.EventArgs e)
??? ...{
??????? XmlDocument xmlDoc = new XmlDocument();
??????? xmlDoc.Load(Server.MapPath("bookstore.xml"));
??????? XmlNodeList xnl = xmlDoc.SelectSingleNode("bookstore").ChildNodes;//獲取bookstore節點的所有子節點
?????? foreach (XmlNode xn in xnl)
?????? ...{????
?????????? XmlElement xe=(XmlElement)xn;????
?????????? if(xe.GetAttribute("genre")=="fantasy")????
?????????? ...{????????
?????????????? xe.RemoveAttribute("genre");//刪除genre屬性????
?????????? }????
?????????? else if(xe.GetAttribute("genre")=="update李贊紅")????
?????????? ...{????????
?????????????? xe.RemoveAll();//刪除該節點的全部內容????
?????????? }
?????? }
?????? xmlDoc.Save(Server.MapPath("bookstore.xml"));//保存
??? }
刪除后的結果為：

<?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>本文來自:.Net中文社區(www.aspxcs.net) 詳細出處參考：http://www.aspxcs.net/HTML/17185862.html

轉載于:https://www.cnblogs.com/opper/archive/2009/09/29/1576255.html

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