RSS提要Ebay C＃

Question

I am currently using the code

     string[] toSearch = { "title", "link", "description" };
        string url = "http://www.ebay.co.uk/sch/i.html?_sacat=0&_from=R40&_nkw=" + itemToSearch.Replace(" ", "+") + "&_sop=15&_rss=1";
        WebRequest request = WebRequest.Create(url);
        WebResponse responce = request.GetResponse();
        Stream rssStream = responce.GetResponseStream();
        XmlDocument rssDocument = new XmlDocument();
        rssDocument.Load(rssStream);
        XmlNodeList rssItems = rssDocument.SelectNodes("channel/item");
        int xMax = toSearch.Length;
        int yMax = rssItems.Count;
        String[,] tempRssData = new String[yMax + 1, xMax];
        for (int i = 0; i < rssItems.Count; ++i)
        {
            XmlNode rssNode = null;
            for (int ii = 0; ii < toSearch.Length; ++ii)
            {
                rssNode = rssItems.Item(i).SelectSingleNode(toSearch[ii]);
                if (rssNode != null)
                {
                    tempRssData[i, ii] = rssNode.InnerText;
                }
                else
                {
                    tempRssData[i, ii] = "";
                }
            }
        }

but rssItems.Count = 0, Does anyone know why. the example of the rss feed I am using is http://www.ebay.co.uk/sch/i.html?_sacat=0&_from=R40&_nkw=raspberry+pi&_sop=15&_rss=1

Answer 1

Your XPath is wrong.

I would suggest you learn how to use XPath correctly by inspecting the XPath spec and looking at tutorials online.

To fix the problem, you will need to change:

XmlNodeList rssItems = rssDocument.SelectNodes("channel/item");

to:

XmlNodeList rssItems = rssDocument.SelectNodes("//channel/item");

You can also execute XPath queries natively in Chrome. Open your RSS feed page in Chrome, open the Developer Tools, open the Console and type in:

$x("expression")

so it becomes:

$x("channel/item")

Which, you should notice, returns nothing.