无法将类型为“System.Xml.XmlComment”的对象强制转换为类型“System.Xml.XmlElement”。

Question

  if (result == "del")
            {
                string id = Convert.ToString(Request.QueryString["id"]);
                XmlDocument xmlDoc = new XmlDocument();
                xmlDoc.Load(Server.MapPath("../Ch/swf/pic.xml"));
                XmlNode root = xmlDoc.SelectSingleNode("folio");
                XmlNodeList xnl = xmlDoc.SelectSingleNode("folio").ChildNodes;
                for (int j = 0; j < xnl.Count; j++)
                {
                    XmlNode xn = xnl.Item(j);
                    XmlElement xe = (XmlElement)xnl.Item(j);  //这个报错                   
                    if(xe["ID"].InnerText == id.ToString())
                    {
                        root.RemoveChild(xe);
                        break;                    }
                }
                xmlDoc.Save(Server.MapPath("../Ch/swf/pic.xml"));
            }求高手解决

Answer 1

修改为：
for (int j = 0; j < xnl.Count; j++)
  {
  XmlNode xn = xnl[j];
  if(xe["ID"].InnerText == id.ToString())
  {
   root.RemoveChild(xn);
   break;  }
  }

Answer 2

XmlElement xe =xnl.Item(j) as XmlElement ; ??/这样貌似也不行

Answer 3

if(xn is XmlElement){
...
}else if(xn is XmlComment){
...

Answer 4

我这问题还是出在添加上，原先XML里面有的图片都能删除，我自己添加的图片就不能删除

Answer 5

Random ran = new Random();
            int id = ran.Next(1000, 9999);
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load(Server.MapPath("../Ch/swf/pic.xml"));
            XmlNode root = xmlDoc.SelectSingleNode("folio");//查找<bcaster>
            XmlElement xe1 = xmlDoc.CreateElement("image");//创建一个<item>节点                     XmlElement xesub3 = xmlDoc.CreateElement("thumbnail"); //添加person节点的里的节点
            xesub3.InnerText = Convert.ToString(Request.Form["thumbnail"]);
            xe1.AppendChild(xesub3);
            XmlElement xesub1 = xmlDoc.CreateElement("pic"); //添加person节点的里的节点
            xesub1.InnerText = Convert.ToString(Request.Form["pic"]);
            xe1.AppendChild(xesub1);            XmlElement xesub2 = xmlDoc.CreateElement("url");
            xesub2.InnerText = Convert.ToString(Request.Form["url"]);
            xe1.AppendChild(xesub2);            XmlElement xesub4 = xmlDoc.CreateElement("ID");
            xesub4.InnerText = id.ToString();
            xe1.AppendChild(xesub4);
            //XmlElement xesub5 = xmlDoc.CreateElement("text_low");
            //xesub5.InnerText = Convert.ToString(Request.Form["text_low"]);
            //xe1.AppendChild(xesub5);            root.AppendChild(xe1);//添加到<bcaster>节点中
            xmlDoc.Save(Server.MapPath("../Ch/swf/pic.xml"));
            Alert.GoParent("flash-list.aspx");        }
        else if (action == "edit")
        {
            string id = Convert.ToString(Request.QueryString["id"]);
            Alert.Show(id.ToString());
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load(Server.MapPath("../Ch/swf/pic.xml"));
            XmlNode root = xmlDoc.SelectSingleNode("folio");
            XmlNodeList xnl = xmlDoc.SelectSingleNode("folio").ChildNodes;
            for (int i = 0; i < xnl.Count; i++)
            {
                XmlElement xe = (XmlElement)xnl.Item(i);
                if (xe["ID"].InnerText == id.ToString())
                {
                    xe["thumbnail"].InnerText = Convert.ToString(Request.Form["thumbnail"]);
                    xe["pic"].InnerText = Convert.ToString(Request.Form["pic"]);
                    xe["url"].InnerText = Convert.ToString(Request.Form["url"]);
                    //xe.SetAttribute("itemtitle", "" + this.FlashText.Value + "");
                }
            }
           
            xmlDoc.Save(Server.MapPath("../Ch/swf/pic.xml"));
            Alert.GoParent("flash-list.aspx");
        }        if (Convert.ToString(Request.QueryString["result"]) == "edit")
        {            string id = Convert.ToString(Request.QueryString["id"]);
            Alert.ShowAndGo(id.ToString() + "aaa", "flash-edit.aspx?result=edit&id=8294");
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load(Server.MapPath("../Ch/swf/pic.xml"));
            XmlNode root = xmlDoc.SelectSingleNode("folio");
            XmlNodeList xnl = xmlDoc.SelectSingleNode("folio").ChildNodes;
            for (int i = 0; i < xnl.Count; i++)
            {
                XmlElement xe = (XmlElement)xnl.Item(i);
                if (xe["ID"].InnerText == id.ToString())
                {
                    xe["thumbnail"].InnerText = Convert.ToString(Request.Form["thumbnail"]);
                    xe["pic"].InnerText = Convert.ToString(Request.Form["pic"]);
                    xe["url"].InnerText = Convert.ToString(Request.Form["url"]);
                    //xe.SetAttribute("itemtitle", "" + this.FlashText.Value + "");
                }
            }            xmlDoc.Save(Server.MapPath("../Ch/swf/pic.xml"));
            Alert.GoParent("flash-list.aspx");
        }
这是编辑的代码，显示那边删除就报那个错

Answer 6

http://hi.baidu.com/liyun_love_it/blog/item/e97b16a9a1b15cbccb130cfd.html