C# 写入XML方法

我们要写入的XML文档内容为

<?xml version="1.0" encoding="UTF-8"?> 
<Contacts> 
  <Contact id="01"> 
    <Name>Daisy Abbey</Name> 
    <Gender>female</Gender> 
  </Contact>   
</Contacts>

（1）使用XmlDocument类：

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）使用LINQ to XML 的XDocument类：

var doc = new XDocument( 
    new XElement("Contacts", 
        new XElement("Contact", 
            new XAttribute("id", "01"),                
            new XElement("Name", "Daisy Abbey"), 
            new XElement("Gender", "female") 
        ) 
    ) 
);    
doc.Save("test2.xml"); 

（3） 使用XmlTextWriter类：

String filename = String.Concat("test3.xml");
using (StreamWriter sw = new StreamWriter(filename))
{
    // Create Xml Writer.
    XmlTextWriter xmlWriter = new XmlTextWriter(sw);

    // 也可以使用public XmlTextWriter(string filename, Encoding encoding)来构造
    // encoding默认为 UTF-8.
    //XmlTextWriter writer = new XmlTextWriter("test3.xml", null);

    // Set indenting so that its easier to read XML when open in Notepad and such apps. 
    xmlWriter.Formatting = Formatting.Indented;

    // This will output the XML declaration
    xmlWriter.WriteStartDocument();
                
    xmlWriter.WriteStartElement("Contacts");

    xmlWriter.WriteStartElement("Contact");
    xmlWriter.WriteAttributeString("id", "01");

    xmlWriter.WriteElementString("Name", "Daisy Abbey");
    xmlWriter.WriteElementString("Gender", "female");                

    // close contact </contact>
    xmlWriter.WriteEndElement();
    // close contacts </contact>
    xmlWriter.WriteEndElement();

    xmlWriter.WriteEndDocument();

    xmlWriter.Close();
}

从上面的代码基本上还是可以看出来，使用LINQ to XML是最简便的。