Xpath Query not returning results

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Xpath Query not returning results

Last post 04-07-2006 1:49 PM by rstackhouse. 2 replies.

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Xpath Query not returning results

03-13-2006, 11:25 AM

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30 point Member
rstackhouse
Member since 07-01-2005, 1:20 PM
Posts 6

I am trying to create a proxy file that will support RSS 1.0/2.0 feeds for a Flash RSS Reader. For the part that parses RSS 1.0 feeds, I have been trying the following without sucess:

string feed = http://www.moock.org/blog/index.rdf;

string channelTitle = "";

string channelLink = "";

string channelDescription = "";

System.Xml.XmlDocument xmlDoc = new XmlDocument();

xmlDoc.Load(feed);

XmlNamespaceManager nsmgr = new XmlNamespaceManager(xmlDoc.NameTable);

nsmgr.AddNamespace("rdf", "http://www.w3.org/1999/02/22-rdf-syntax-ns#");

nsmgr.AddNamespace("dc", "http://purl.org/dc/elements/1.1/");

nsmgr.AddNamespace("sy", "http://purl.org/rss/1.0/modules/syndication/" );

nsmgr.AddNamespace("admin", "http://webns.net/mvcb/" );

nsmgr.AddNamespace("cc", "http://web.resource.org/cc/" );

nsmgr.AddNamespace("prfx1", "http://purl.org/rss/1.0/");

XmlElement root = xmlDoc.DocumentElement;

XmlNodeList nodeList = root.SelectNodes("//prfx1:item", nsmgr);

if(nodeList.Count > 0)

{

nodeList = root.SelectNodes("//prfx1:channel/title", nsmgr);

if(nodeList.Count > 0)

channelTitle = nodeList[0].Value;

nodeList = root.SelectNodes("//prfx1:channel/link", nsmgr);

if(nodeList.Count > 0)

channelLink = nodeList[0].Value;

nodeList = root.SelectNodes("//prfx1:channel/description", nsmgr);

if(nodeList.Count > 0)

channelDescription = nodeList[0].Value;

nodeList = root.SelectNodes("//prfx1:item/title", nsmgr);

string[] titles = new string[nodeList.Count];

int i = 0;

foreach(XmlNode title in nodeList)

{

titles[i] = title.Value;

i++;

}

nodeList = root.SelectNodes("//prfx1:item/link", nsmgr);

string[] links = new string[nodeList.Count];

i = 0;

foreach(XmlNode link in nodeList)

{

links[i] = link.Value;

i++;

}

nodeList = root.SelectNodes("//prfx1:item/description", nsmgr);

string[] descriptions = new string[nodeList.Count];

i = 0;

foreach(XmlNode description in nodeList)

{

descriptions[i] = description.Value;

i++;

}

Response.Write("<?xml version=\"1.0\"?>");

Response.Write("<rss version=\"2.0\">");

Response.Write("<channel>");

Response.Write("<title>"+channelTitle+"</title>");

Response.Write("<link>"+channelLink+"</link>");

Response.Write("<description>"+channelDescription+"</description>");

for(i = 0; i < titles.Length; i++)

{

Response.Write("<item>");

Response.Write("<title>"+titles[i]+"</title>");

Response.Write("<link>"+links[i]+"</link>");

Response.Write("<description>"+descriptions[i]+"</description>");

Response.Write("</item>");

}

Response.Write("</channel>");

Response.Write("</rss>");

}

As you can see, I've even tried creating a prefix for a namespace without one in the document as this thread suggested http://forums.asp.net/495107/ShowPost.aspx. The document itself seems to be well formed, but when I try something like root.SelectNodes("//channel"), I get nothing back. Conversely, if I try root.OuterXml, I get the entire document back.

Could someone please tell me where I am going wrong here?

Re: Xpath Query not returning results

03-14-2006, 3:18 PM

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90 point Member
swordfish666
Member since 10-30-2002, 5:10 AM
US
Posts 18

Try this:

XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load("index.rdf");//from a loacl file
            XmlNodeList xNodeList =xmlMap.SelectNodes("//channel");
            foreach(XmlNode xNode in xNodeList)
            {
                if(xNode.Name == "NODE YOU ARE LOOKING FOR")
                {
                    //do something with xNode<br>
                }
            }

Someties using the proper methods just don't work as well as keeping it simple

Re: Xpath Query not returning results

04-07-2006, 1:49 PM

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30 point Member
rstackhouse
Member since 07-01-2005, 1:20 PM
Posts 6

I added this:

else
                {
                    //xNodeIterator.Count = 0

                    System.Xml.XmlDocument xmlDoc = new XmlDocument();
                    xmlDoc.Load("http://www.moock.org/blog/index.rdf");
                    Response.Write("xmlDoc.FirstChild.Name: "+xmlDoc.FirstChild.Name+"\n");
                    Response.Write("xmlDoc.FirstChild.HasChildNodes: "+xmlDoc.FirstChild.HasChildNodes);
                }

and the response i got was this:

xmlDoc.FirstChild.Name: xml
xmlDoc.FirstChild.HasChildNodes: FalsexmlDoc.FirstChild.Name: xml
xmlDoc.FirstChild.HasChildNodes: False

Something tells me this type of document isn't liked by the parser. Any suggestions?

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