Help with Namespaces and XElement.Load RSS

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  randy4921

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  Help with Namespaces and XElement.Load

  May 09, 2012 04:46 PM|LINK

  I have an XML data set coming into my C# app using the following:

  var _xml = XElement.Load("http://myserver:8080/myxmlfile.xml").Elements("ns:results");

  This works great as long as there is no namespace specified in the xml data coming in i.e. ...Element("results"). But if there is a namespace specified in the xml data coming in i.e. "ns" (see above)  I get an error i.e. the ":" character is not recognized. So, it seems using the above the namespace is not recognized and it bombs.

  I've looked at namespacemanager examples but they all seem to talk about reading a "table". All I need is for the above XElement load to recognize the namespace and go about it's business as usual.

  I've tried:

  XmlNamespaceManager nsmanager = new XmlNamespaceManager("http://myserver:8080)/incomingxmlfile.xml");

  nsmanager.AddNamespace("ns", "http://logic.com/somenamespacename")

  But this format is not recognized.

  Thanks for any help!

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  Decker Dong ...

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  Re: Help with Namespaces and XElement.Load

  May 11, 2012 01:29 AM|LINK

  randy4921

  XmlNamespaceManager nsmanager = new XmlNamespaceManager("http://myserver:8080)/incomingxmlfile.xml");

  XmlNamespaceManager needs a parameter that XmlDataTable。So you cannot assign a string value to it——you have to use something like XmlTextReader to assign the NameTable as the value of XmlDataTable：

  And there's something wrong with your url——"http://myserver:8080)/incomingxmlfile.xml"——Notice you've got a ")"；and maybe it is：

  http://myserver:8080/incomingxmlfile.xml

  【Sample From MSDN】

  XmlTextReader reader = new XmlTextReader("myfile.xml");
  XmlNamespaceManager nsmanager = new XmlNamespaceManager(reader.NameTable);
  nsmanager.AddNamespace("msbooks", "www.microsoft.com/books");
  nsmanager.PushScope();
  nsmanager.AddNamespace("msstore", "www.microsoft.com/store");
  while (reader.Read())
  {
      Console.WriteLine("Reader Prefix:{0}", reader.Prefix);
      Console.WriteLine("XmlNamespaceManager Prefix:{0}",
      nsmanager.LookupPrefix(nsmanager.NameTable.Get(reader.NamespaceURI)));
  }

  
  
  

  • Marked as answer by decker dong - msft on May 15, 2012 01:50 AM
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  randy4921

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  Re: Help with Namespaces and XElement.Load

  Jun 07, 2012 07:51 PM|LINK

  Sorry about the typo in the url.

  Also, sorry I don't have very much experience with LINQ.

  I had success with LINQ when I was receiving a string of xml results WITH NO NAMESPACE from of an xquery via http. Like this:

  var _xml = XElement.Load("http//server1:8080/index.xqy").Elements("results")

  But when I had another xml data set WITH NAMWSPACES it bombed with an error like "the character ":" is not recognized".

  My http call was like the above but the xml data set returned had namespace like this:

  <ns:results xmlns:ns="http://something.com/ns">

     <map:facet name="genre">

        <map:facet name="genre">

           <map:result>

             <map:value>Pop</map:value>

             <map:inQuery>false</map:inQuery>

             <map:count>248</map:count>

  .

  .

  .

  var _xml = XElement.Load("http//server1:8080/index.xqy").Elements("map:results")

  So, in this context is there a way to tell LINQ that namespaces are present, read them and return them just like before?

  Thanks for any help!

  randy
  

  
  

  
  

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  Decker Dong ...

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  Re: Help with Namespaces and XElement.Load

  Jun 08, 2012 01:14 AM|LINK

  randy4921

  But when I had another xml data set WITH NAMWSPACES it bombed with an error like "the character ":" is not recognized".

  Sorry but you should use 

  XmlNamespaceManager nsmanager = new XmlNamespaceManager(reader.NameTable);

  to load the defined namespaces first，and then you can use：

  XmlDocument's SelectNodes("Your Node Path",nsmanager);

  For msdn you can see：

  【xml】
  <?xml version="1.0"?>
  <!-- A fragment of a book store inventory database -->
  <bookstore xmlns:bk="urn:samples">
    <book genre="novel" publicationdate="1997" bk:ISBN="1-861001-57-8">
      <title>Pride And Prejudice</title>
      <author>
        <first-name>Jane</first-name>
        <last-name>Austen</last-name>
      </author>
      <price>24.95</price>
    </book>
    <book genre="novel" publicationdate="1992" bk:ISBN="1-861002-30-1">
      <title>The Handmaid's Tale</title>
      <author>
        <first-name>Margaret</first-name>
        <last-name>Atwood</last-name>
      </author>
      <price>29.95</price>
    </book>
    <book genre="novel" publicationdate="1991" bk:ISBN="1-861001-57-6">
      <title>Emma</title>
      <author>
        <first-name>Jane</first-name>
        <last-name>Austen</last-name>
      </author>
      <price>19.95</price>
    </book>
    <book genre="novel" publicationdate="1982" bk:ISBN="1-861001-45-3">
      <title>Sense and Sensibility</title>
      <author>
        <first-name>Jane</first-name>
        <last-name>Austen</last-name>
      </author>
      <price>19.95</price>
    </book>
  </bookstore>
  
  【cs codes】
  using System;
  using System.IO;
  using System.Xml;
  
  public class Sample
  {
    public static void Main()
    {
        XmlDocument doc = new XmlDocument();
        doc.Load("booksort.xml");
  
        //Create an XmlNamespaceManager for resolving namespaces.
        XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
        nsmgr.AddNamespace("bk", "urn:samples");
  
        //Select and display the value of all the ISBN attributes.
        XmlNodeList nodeList;
        XmlElement root = doc.DocumentElement;
        nodeList = root.SelectNodes("/bookstore/book/@bk:ISBN", nsmgr);
        foreach (XmlNode isbn in nodeList){
          Console.WriteLine(isbn.Value);
        }
     }
  }

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  randy4921

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  Re: Help with Namespaces and XElement.Load

  Jun 15, 2012 04:35 PM|LINK

  Thanks for the reply. I tried what was suggested but it turns out that my xml data that is coming in is the result of an xquery from a server database and not an xml file on a file system i.e. xmlfile.xml. When I tried the above (i.e. I made it like it was an xml document coming in)  I got an error that said, "Data at the root level is invalid. Line 1, position 1". Of coure there is no utf info like in a valid or well formed xml file.

  My http call was like the above but the xml data set returned had namespace like this:

  <map:results xmlns:ns="http://something.com/map">

     <map:facet name="genre">

        <map:facet name="genre">

           <map:result>

             <map:value>Pop</map:value>

             <map:inQuery>false</map:inQuery>

             <map:count>248</map:count>

  .

  .

  .

  var _xml = XElement.Load("http//server1:8080/index.xqy").Elements("map:results")

  So, it seems I can't get .net or LINQ to recognize namespaces if it is not an .xml file read from disk.

  Does this mean .net can't handle namespaces that are part of an xml stream like the data example I gave above?

  What to do? Could so something goofy like build an xml file from the xml stream, write it to disk, then read it back in just so the namespace problem can be worked around.

  ugh! Any help appreciated.

  Randy
  

  
  

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  Decker Dong ...

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  Re: Help with Namespaces and XElement.Load

  Jun 16, 2012 02:18 AM|LINK

  randy4921

  Elements("map:results")

  sorry for any kind of self-defined namespace，you CANNOT do directly like what you did to a general common tag name……；What you can do is just use XNameSpace.Get("Your xmlns's address) plus the suffix——

  var _xml = XElement.Load("http//server1:8080/index.xqy").Elements(XNameSpace.Get("xmlns's Address of map")+"results")

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  randy4921

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  Re: Help with Namespaces and XElement.Load

  Jun 18, 2012 06:40 PM|LINK

  
  

  Thanks much for the reply.
  
  When I saw your suggestion I thought for sure it would work. However, I'm still gettin a "null" data set returned.
  
  This is what I did:
  
  var _xmltemp = XElement.Load("http//server1:8080/index.xqy")
  
  In the Visual Studio debugger when I veiw the xml data from the source it looks just like I expect.
  
  This is it:
  

  <map:results xmlns:map="http://something.com/map">

     <map:facet name="genre">

        <map:facet name="genre">

           <map:result>

             <map:value>Pop</map:value>

             <map:inQuery>false</map:inQuery>

             <map:count>248</map:count>

  . etc....

  But when I get to the next statement in the debugger which is:

  
  var _xml =_xmltemp.Elements(XNameSpace.Get("http://something.com/map")+"results")
  

   the variable _xml is null.
  
  Does this look correct? Did I miss something?

  Again, thanks for the reply. I thought you had fixed my problem and maybe you have but I have some error.

  Randy
  

  • Edited by randy4921 on Jun 18, 2012 09:46 PM
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  randy4921

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  Re: Help with Namespaces and XElement.Load

  Jun 18, 2012 11:18 PM|LINK

  All,

  Looks like the results ARE coming back. The debugger was showing null but data was really there.

  Thanks much for the help.

  I think this is resolved.

  Randy

  • Marked as answer by decker dong - msft on Jun 19, 2012 01:14 AM