把文本框的值写入到xml文件中

 protected void btn_write_Click(object sender, EventArgs e)
    {
        XmlWriterSettings settings=new XmlWriterSettings();
        settings.Indent=true;
        settings.IndentChars=" ";
        using (XmlWriter write = XmlWriter.Create("E:\books.xml",settings))
        {
            write.WriteStartElement("book");
            write.WriteElementString("price", txt_content.Text);
            write.Flush();
        }
}