编写XML XmlTextWriter与XmlDocument

XmlTextWriter类可以把XML写入一个流、文件或TextWriter对象中。

简单例子：
  private void button2_Click(object sender, System.EventArgs e)
  {
   string filename = "booknew.xml";
   XmlTextWriter tw = new XmlTextWriter(filename,null);
   tw.Formatting = Formatting.Indented;
   tw.WriteStartDocument();
   
   tw.WriteStartElement("book");
   tw.WriteAttributeString("genre","Mystery");
   tw.WriteAttributeString("publicationdate","2001");
   tw.WriteAttributeString("ISBN","123456789");
   tw.WriteElementString("title","Case of the Missing Cookie");
   tw.WriteStartElement("author");
   tw.WriteElementString("name","Cookie Monster");
   tw.WriteEndElement();
   tw.WriteElementString("price","9.99");
   tw.WriteEndElement();
   tw.WriteEndDocument();
   tw.Flush();
   tw.Close();
  }

代码生成后的xml文档booksnew.xml：

<?xml version="1.0"?>
<book genre="Mystery" publicationdate="2001" ISBN="123456789">
  <title>Case of the Missing Cookie</title>
  <author>
    <name>Cookie Monster</name>
  </author>
  <price>9.99</price>
</book>

可 以看出，在XML文档中，有一个起始方法和结束方法（WriteStartElement和WriteEndElement）,其他专用的写入方 法：WriteCData可以输入一个Cdata；WriteComment以正确的XML格式写入注释。WriteChars写入字符缓冲区的内容。

利用.NET DOM,XmlDocument创建一个文档

  private XmlDocument doc= new XmlDocument();
  private void button2_Click(object sender, System.EventArgs e)
  {
     XmlDeclaration newDec = doc.CreateXmlDeclaration("1.0",null,null);
     doc.AppendChild(newDec);
     XmlElement newRoot = doc.CreateElement("newBookstore");
     doc.AppendChild(newRoot);

     //创建一个新的book元素
     XmlElement newBook = doc.CreateElement("book");
     //创建并设置book元素的属性
     newBook.SetAttribute("genre","Mystery");
     newBook.SetAttribute("publicationdate","2001");
     newBook.SetAttribute("ISBN","123456789");
     //创建一个title元素
     XmlElement newTilte = doc.CreateElement("title");
     newTilte.InnerText  ="Case of the Missing Cookie";
     newBook.AppendChild(newTilte);
     //创建author元素
     XmlElement newAuthor = doc.CreateElement("author");
     newBook.AppendChild(newAuthor);

     XmlElement newName = doc.CreateElement("name");
     newName.InnerText  = "C.Monster";
     newAuthor.AppendChild(newName);

     XmlElement newPrice = doc.CreateElement("price");
     newPrice.InnerText = "9.95";
     newBook.AppendChild(newPrice);
     doc.DocumentElement.AppendChild(newBook);
     XmlTextWriter tr = new XmlTextWriter("booksEdit.xml",null);
     tr.Formatting = Formatting.Indented;
     doc.WriteContentTo(tr);
     tr.Close();
}

代码生成后的文档：
<?xml version="1.0"?>
<newBookstore>
  <book genre="Mystery" publicationdate="2001" ISBN="123456789">
    <title>Case of the Missing Cookie</title>
    <author>
      <name>C.Monster</name>
    </author>
    <price>9.95</price>
  </book>
</newBookstore>