xml change

            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load("bookstore.xml");
            XmlNodeList nodeList = xmlDoc.SelectSingleNode("bookstore").ChildNodes;//获取bookstore节点的所有子节点  
            foreach (XmlNode xn in nodeList)//遍历所有子节点  
            {
                XmlElement xe = (XmlElement)xn;//将子节点类型转换为XmlElement类型  
                if (xe.GetAttribute("genre") == "红")//如果genre属性值为“红”  
                {
                    xe.SetAttribute("genre", "update红");//则修改该属性为“update红”  
                    XmlNodeList nls = xe.ChildNodes;//继续获取xe子节点的所有子节点  
                    foreach (XmlNode xn1 in nls)//遍历  
                    {
                        XmlElement xe2 = (XmlElement)xn1;//转换类型  
                        if (xe2.Name == "author")//如果找到  
                        {
                            xe2.InnerText = "亚胜";//则修改  
                            break;//找到退出来就可以了  
                        }
                    }
                    break;
                }
            }
            xmlDoc.Save("bookstore.xml");//保存。