C# XML操作

public static void Main()   
        {
            string ids="1,2,3,4,5,6,9";
            string filePath = "c://c/d/qq.xml";
            string xmlPath = "getsomething/news/list/store";
            string subString = xmlPath.Substring(0,xmlPath.LastIndexOf('/'));
            string now = xmlPath.Substring(xmlPath.LastIndexOf('/')+1);
            
            if (!IsExists(filePath))
            {
                Exists(filePath);
            }
            doc.Load(filePath);
            xml = (XmlElement)doc.FirstChild;
            string parentPath = xmlPath.Substring(0, xmlPath.LastIndexOf('/'));
            string nowNode = xmlPath.Substring(xmlPath.LastIndexOf('/') + 1);
            XmlNode node = doc.SelectSingleNode(parentPath);
            XmlNode oldNode = doc.SelectSingleNode(xmlPath);
            if (node == null)
            {
                node = CreateXmlNode(parentPath);
                XmlElement el = doc.CreateElement(nowNode);
                XmlAttribute attr = doc.CreateAttribute("ids");
                attr.Value = ids;
                el.Attributes.Append(attr);
                node.AppendChild(el);
            }
            else
            {
                XmlElement el = doc.CreateElement(nowNode);
                XmlAttribute attr = doc.CreateAttribute("ids");
                attr.Value = ids;
                el.Attributes.Append(attr);
                if (oldNode == null)
                {
                    node.AppendChild(el);
                }
                else
                {
                    node.ReplaceChild(el, oldNode);
                }
            }
            doc.Save(filePath);
            Console.ReadKey();
        }


 public static XmlNode CreateXmlNode(string xmlPath)
        {
            string[] xmls = xmlPath.Split('/');
            string root = "";
            XmlNode parent =xml;
            for (int i = 0; i < xmls.Length;i++)
            {
                XmlNode node = doc.DocumentElement.SelectSingleNode(root+"/"+xmls[i]);
                if (node == null)
                {
                    XmlElement xmle = doc.CreateElement(xmls[i]);
                    parent.AppendChild(xmle);
                }
                root = root + "/" + xmls[i];
                parent =doc.DocumentElement.SelectSingleNode(root);
            }
            return parent;
        }