C# 读写xml文件总结 [详细]

C#写入xml文件

1、XmlDocument

1。我认为是最原始，最基本的一种：利用XmlDocument向一个XML文件里写节点，然后再利用XmlDocument保存文件。
首先加载要写入的XML文件，但是如果没有的，就要新建，在新建的过程中，要有写入的代码；

XmlDocument doc = new XmlDocument();try{doc.Load("new.xml");}catch{XmlTextWriter xtw = new XmlTextWriter("new.xml", Encoding.UTF8);//新建XML文件        xtw.WriteStartDocument();xtw.WriteStartElement("gnode");// gnode根节点                 xtw.WriteStartElement("myxm1");// gnode根节点下的元素myxmls             xtw.WriteEndElement();xtw.WriteEndElement();xtw.WriteEndDocument();xtw.Close();doc.Load("new.xml");}XmlNode xn = doc.DocumentElement;//找到根节点     XmlElement xe = doc.CreateElement("myxml2");//在根节点下创建元素，如果是属性，则用XmlAttribute； xe.InnerText = "薪薪代码hahaha";//给子节点写入文本节点（值）     xn.AppendChild(xe);//根节点将其纳入         doc.Save("new2.xml");//利用XmlDocument保存文件}

注意点：在新建根节点的时候，WriteStartElement，只能嵌套，也就是只能有一个根节点。

2、DataSet对象里的值来生成XML文件

应用到数据库，将数据库的DataSet对象里的值来生成XML文件的元素；

using (SqlConnection con = new SqlConnection("Server=.;DataBase=HGSTUDY;uid=sa;pwd=yao")){con.Open();SqlCommand command = new SqlCommand("select * from GL_STUDY", con);command.CommandType = CommandType.Text;DataSet ds = new DataSet("DATASET");//DATASET将成为XML文件中的根节点名称，否则系统将其命名为NewDataSet      SqlDataAdapter sda = new SqlDataAdapter();sda.SelectCommand = command;sda.Fill(ds, "DATATABLE");//DATATABLE为所生成XML文件中的子节点名称，否则系统将其命名为Table。   ds.WriteXml("dbxml.xml");// DataSet的方法WriteXml将数据写入到XML文件，就是这么一句话。如果不保存到文件，直接ds.GetXML()      }

3、利用XmlSerializer来将类的属性值转换为XML文件的元素值。

用一个字符串作为一个XML文档中的xmlAttribute或xmlElement。[其元素或属性由类的定义来设置(xml串行化)]

using System;System.xml.Serialization;

1. 先初始化一个类，设置属性值

var xmlDoc = new XmlDocument();
//Create the xml declaration first
xmlDoc.AppendChild(xmlDoc.CreateXmlDeclaration("1.0", "utf-8", null));
//Create the root node and append into doc
var el = xmlDoc.CreateElement("Contacts");
xmlDoc.AppendChild(el);
// Contact
XmlElement elementContact = xmlDoc.CreateElement("Contact");
XmlAttribute attrID = xmlDoc.CreateAttribute("id");
attrID.Value = "01";
elementContact.Attributes.Append(attrID);
el.AppendChild(elementContact);
// Contact Name
XmlElement elementName = xmlDoc.CreateElement("Name");
elementName.InnerText = "Daisy Abbey";
elementContact.AppendChild(elementName);
// Contact Gender
XmlElement elementGender = xmlDoc.CreateElement("Gender");
elementGender.InnerText = "female";
elementContact.AppendChild(elementGender);
xmlDoc.Save("test1.xml");

2. 建XmlSerializer实例

class XXX {  XmlSerializer ser = new XmlSerializer(Type.GetType("forxml.truck"));   Truck tr = new Truck();     tr.ID = 1;    tr.cheID = "赣A T34923";}

3. Serialize方法–完成对类的串行化

XmlTextWriter xtw = new XmlTextWriter("myxml.xml",Encoding.UTF8); 用XmlTextWriter 创建一个XML文件   ser.Serialize(xtw, tr);      //如果只想显示，可以直接ser.Serialize(Console.Out, tr);
}

xml常用方法：
定义xml文档：XmlDocument xmlDoc = new XmlDocument();
初始化xml文档：xmlDoc.Load(“D:\\book.xml”);//找到xml文件
创建根元素：XmlElement xmlElement = xmlDoc.CreateElement(“”, “Employees”, “”);
创建节点：XmlElement xeSub1 = xmlDoc.CreateElement(“title”);
查找Employees节点：XmlNode root = xmlDoc.SelectSingleNode(“Employees”);
添加节点：xe1.AppendChild(xeSub1);
更改节点的属性：xe.SetAttribute(“Name”, “李明明”);
移除xe的ID属性：xe.RemoveAttribute(“ID”);
删除节点title：xe.RemoveChild(xe2);

示例：写入xml

1、创建xml文档

public void CreateXMLDocument()
{XmlDocument xmlDoc = new XmlDocument();          
//加入XML的声明段落,<?xml version="1.0" encoding="gb2312"?>XmlDeclaration xmlDeclar;xmlDeclar = xmlDoc.CreateXmlDeclaration("1.0", "gb2312", null);xmlDoc.AppendChild(xmlDeclar);          //加入Employees根元素XmlElement xmlElement = xmlDoc.CreateElement("", "Employees", "");xmlDoc.AppendChild(xmlElement);        //添加节点XmlNode root = xmlDoc.SelectSingleNode("Employees");XmlElement xe1 = xmlDoc.CreateElement("Node");xe1.SetAttribute("Name", "薪薪代码");xe1.SetAttribute("ISB", "2-3631-4");        //添加子节点XmlElement xeSub1 = xmlDoc.CreateElement("title");xeSub1.InnerText = "学习VS";xe1.AppendChild(xeSub1);XmlElement xeSub2 = xmlDoc.CreateElement("price");xe1.AppendChild(xeSub2);XmlElement xeSub3 = xmlDoc.CreateElement("weight");xeSub3.InnerText = "20";xeSub2.AppendChild(xeSub3);root.AppendChild(xe1);xmlDoc.Save("D:\\\\book.xml");//保存的路径
}

生成的xml文件如下：

<?xml version="1.0" encoding="GB2312"?>
-<Employees>-<Node ISB="2-3631-4" Name="薪薪代码"><title>学习VS</title>-<price><weight>20</weight></price></Node>
</Employees>

2 、增加节点

XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load("D:\\\\book.xml");//找到xml文件
XmlNode root = xmlDoc.SelectSingleNode("Employees");//查找Employees节点
XmlElement xe1 = xmlDoc.CreateElement("Node2");//添加Node2节点
xe1.SetAttribute("Name", "张飞");
XmlElement xeSub1 = xmlDoc.CreateElement("title");//定义子节点
xeSub1.InnerText = "心情好";
xe1.AppendChild(xeSub1);//添加节点到Node2
root.AppendChild(xe1);//添加节点到Employees
xmlDoc.Save("D:\\\\book.xml");

结果：

<?xml version="1.0" encoding="GB2312"?>-<Employees>-<Node ISB="2-3631-4" Name="薪薪代码"><title>学习VS</title>-<price><weight>20</weight></price></Node>-<Node2 Name="张三"><title>心情好</title></Node2>-<Node2 Name="张三"><title>心情好</title></Node2>
</Employees>

3 、修改节点：

public void ModifyNode()
{XmlDocument xmlDocument = new XmlDocument();xmlDocument.Load("D:\\\\book.xml");XmlNodeList nodeList = xmlDocument.SelectSingleNode("Employees").ChildNodes;//获取Employees节点的所有子节点foreach (XmlNode xn in nodeList)//遍历{XmlElement xe = (XmlElement)xn;if (xe.GetAttribute("Name") == "薪薪代码"){xe.SetAttribute("Name", "薪薪");//更改节点的属性XmlNodeList xnl = xe.ChildNodes;//获取xe的所有子节点foreach (XmlNode xn1 in xnl){XmlElement xe2 = (XmlElement)xn1;//将节点xn1的属性转换为XmlElementif (xe2.Name == "title")//找到节点名字为title的节点{xe2.InnerText = "今天天气不好";}if (xe2.Name == "price"){XmlNodeList xnl2 = xe2.ChildNodes;foreach (XmlNode xn2 in xnl2){if (xn2.Name == "weight"){xn2.InnerText = "88";}}}}}}xmlDocument.Save("D:\\\\book2.xml");
}

运行结果:

<?xml version="1.0" encoding="GB2312"?>
-<Employees>
-<Node ISB="2-3631-4" Name="薪薪">
<title>今天天气不好</title>-<price>
<weight>88</weight>
</price>
</Node>
-<Node2 Name="张三">
<title>心情好</title>
</Node2></Employees>

4 、删除节点

public void DeleteNode()
{XmlDocument xmlDocument = new XmlDocument();xmlDocument.Load("D:\\\\book1.xml");XmlNodeList xnl = xmlDocument.SelectSingleNode("Employees").ChildNodes;foreach (XmlNode xn in xnl){if (xn.Name == "Node"){XmlElement xe = (XmlElement)xn;//将xn的属性转换为XmlElementxe.RemoveAttribute("ID");//移除xe的ID属性XmlNodeList xnl2 = xe.ChildNodes;for (int i = 0; i < xnl2.Count; i++){XmlElement xe2 = (XmlElement)xnl2.Item(i);if (xe2.Name == "title"){xe.RemoveChild(xe2);//删除节点title}}}}xmlDocument.Save("D:\\\\book3.xml");
}

结果：

<?xml version="1.0" encoding="GB2312"?>
-<Employees>
-<Node ISB="2-3631-4" Name="薪薪">-<price>
<weight>20</weight>
</price>
</Node>-
<Node2 Name="张三">
<title>心情好</title>
</Node2>-
<Node2 Name="张三">
<title>心情好</title>
</Node2>
</Employees>

c#读取xml文件

xml文件如下：

<?xml version="1.0" encoding="utf-8" ?>
<configurationN><ServerAddress>1143</ServerAddress><ID>192.168</ID></configurationN>

在写入xml文件时，最主要使用了两个方法：Load和Save。

Load：初始化xml文档，以便项目文件获取具体的xml节点的值。

public void Load(string path)
{try{XmlDocument xmlDocument = new XmlDocument();xmlDocument.Load(path);XmlNodeList xnl = xmlDocument.SelectSingleNode(managerNode).ChildNodes;foreach (XmlNode xn in xnl){if (xn.Name == configuration_ServerAddress){ServerAddress = xn.InnerText;}}}catch(Exception ex){ }
}

Save：在项目系统中进行修改配置文件值后，需要对xml进行重新保存

public void Save(string path)
{try{XmlDocument xmlDocument = new XmlDocument();xmlDocument.Load(path);XmlNodeList xnl = xmlDocument.SelectSingleNode(managerNode).ChildNodes;foreach (XmlNode xn in xnl){if (xn.Name == configuration_ServerAddress){xn.InnerText = ServerAddress;}}xmlDocument.Save(path);}catch (Exception ex){ }
}

此处将所有代码都贴出来，方便下次实现。因为项目是WPF文件，而且都是简单控件，所以只贴出后台代码。

class ConfigurationManager:INotifyPropertyChanged
{public const string managerNode = "configurationN";//根节点public const string configuration_ServerAddress = "ServerAddress";//子节点private string _ServerAddress;public string ServerAddress{get { return _ServerAddress; }set{_ServerAddress = value;NotifyPropertyChanged("ServerAddress");}}public void Load(string path){try{XmlDocument xmlDocument = new XmlDocument();xmlDocument.Load(path);XmlNodeList xnl = xmlDocument.SelectSingleNode(managerNode).ChildNodes;foreach (XmlNode xn in xnl){if (xn.Name == configuration_ServerAddress){ServerAddress = xn.InnerText;}}}catch(Exception ex){ }}public void Save(string path){try{XmlDocument xmlDocument = new XmlDocument();xmlDocument.Load(path);XmlNodeList xnl = xmlDocument.SelectSingleNode(managerNode).ChildNodes;foreach (XmlNode xn in xnl){if (xn.Name == configuration_ServerAddress){xn.InnerText = ServerAddress;}}xmlDocument.Save(path);}catch (Exception ex){ }}public event PropertyChangedEventHandler PropertyChanged;private void NotifyPropertyChanged(string propertyName){if (PropertyChanged != null){PropertyChanged(this, new PropertyChangedEventArgs(propertyName));}}public static ConfigurationManager Instance = new ConfigurationManager();
}public partial class MainWindow : Window
{public MainWindow(){InitializeComponent();Start();this.tb1.Text = ConfigurationManager.Instance.ServerAddress.ToString();}private string path = "CONFIG\\\\System.xml";private void button1_Click(object sender, RoutedEventArgs e){ConfigurationManager.Instance.ServerAddress = this.tb1.Text;ConfigurationManager.Instance.Save(path);}private void button2_Click(object sender, RoutedEventArgs e){Application.Current.Shutdown();}private void Start(){ConfigurationManager.Instance.Load(path);}
}