I am trying to read an XML feed to get the last post date. My xml looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0"
xmlns:content="http://purl.org/rss/1.0/modules/content/"
xmlns:wfw="http://wellformedweb.org/CommentAPI/"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:atom="http://www.w3.org/2005/Atom"
xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
xmlns:slash="http://purl.org/rss/1.0/modules/slash/"
>
<channel>
<title>mysite</title>
<atom:link href="http://www.mysite.com/news/feed/" rel="self" type="application/rss+xml" />
<link>http://www.mysite.com/news</link>
<description>mysite</description>
<lastBuildDate>Tue, 22 Nov 2011 16:10:27 +0000</lastBuildDate>
<language>en</language>
<sy:updatePeriod>hourly</sy:updatePeriod>
<sy:updateFrequency>1</sy:updateFrequency>
<generator>http://wordpress.org/?v=3.0.4</generator>
<item>
<title>My first post!</title>
<link>http://www.mysite.com/news/2011/11/22/docstore-v2-released/</link>
<comments>http://www.mysite.com/news/2011/11/22/docstore-v2-released/#comments</comments>
<pubDate>Tue, 22 Nov 2011 16:10:27 +0000</pubDate>
<dc:creator>mysite</dc:creator>
<category><![CDATA[News]]></category>
<category><![CDATA[Promotions]]></category>
<category><![CDATA[docstore]]></category>
I didn't show all of the xml since it is rather long.
My method, so far, looks like this:
private void button1_Click(object sender, EventArgs e)
{
var XmlDoc = new XmlDocument();
// setup the XML namespace manager
var mgr = new XmlNamespaceManager(XmlDoc.NameTable);
// add the relevant namespaces to the XML namespace manager
mgr.AddNamespace("ns", "http://purl.org/rss/1.0/modules/content/");
var webClient = new WebClient();
var stream = new MemoryStream(webClient.DownloadData("http://www.mysite.com/news/feed/"));
XmlDoc.Load(stream);
// **USE** the XML anemspace in your XPath !!
XmlElement NodePath = (XmlElement)XmlDoc.SelectSingleNode("/ns:Response");
while (NodePath != null)
{
foreach (XmlNode Xml_Node in NodePath)
{
Console.WriteLine(Xml_Node.Name + ": " + Xml_Node.InnerText);
}
}
}
I'm having a problem with it telling me:
Namespace Manager or XsltContext needed. This query has a prefix,
variable, or user-defined function.
All I want to pull out of this xml code is the 'lastBuildDate'. I'm going in circles trying to get this code right.
Can someone tell me what I am doing wrong here?
Thank you!
You're not using the namespace manager.
// **USE** the XML anemspace in your XPath !!
XmlElement NodePath = (XmlElement)XmlDoc.SelectSingleNode("/ns:Response", mgr);
There is only one of the element you are going after, you could go directly to it using the XPath. That element is also in the default namespace, so you do not need to do anything special to get to it. What about:
var XPATH_BUILD_DATE="/rss/channel/lastBuildDate";
private void button1_Click(object sender, EventArgs e){
var xmlDoc = new XmlDocument();
var webClient = new WebClient();
var stream = new MemoryStream(webClient.DownloadData("http://www.mysite.com/news/feed/"));
xmlDoc.Load(stream);
XmlElement xmlNode = (XmlElement)xmlDoc.SelectSingleNode(XPATH_BUILD_DATE);
Console.WriteLine(xmlNode.Name + ": " + xmlNode.InnerText);
}
If you did however need to dig into elements in a different namespace, you can do that also with the XPath (example, getting the dc:creator:
/rss/channel/item[1]/*[local-name() = 'creator']
Related
<?xml version="1.0" encoding="utf-8"?>
<serv:message
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:serv="http://www.webex.com/schemas/2002/06/service" xsi:schemaLocation="http://www.webex.com/schemas/2002/06/service http://www.webex.com/schemas/2002/06/service.xsd">
<header>
<securityContext>
<webExID/>
<password/>
<siteID/>
<partnerID/>
</securityContext>
</header>
<body>
<bodyContent xsi:type="java:com.webex.service.binding.training.CreateTrainingSession"
xmlns="http://www.webex.com/schemas/2002/06/service/training"
xmlns:com="http://www.webex.com/schemas/2002/06/common"
xmlns:sess="http://www.webex.com/schemas/2002/06/session"
xmlns:serv="http://www.webex.com/schemas/2002/06/service"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.webex.com/schemas/2002/06/service/training http://www.webex.com/schemas/2002/06/service/training/trainingsession.xsd">
<sess:accessControl>
<sess:sessionPassword/>
</sess:accessControl>
<sess:schedule></sess:schedule>
<metaData>
<sess:confName/>
<agenda/>
<description/>
<greeting/>
<location/>
</metaData>
<enableOptions>
<chat/>
<poll/>
<audioVideo/>
<fileShare/>
<applicationShare/>
<desktopShare/>
<annotation/>
<fullScreen/>
<voip/>
</enableOptions>
</bodyContent>
</body>
</serv:message>
Above XML is standard VILT Create Event xml and I need to populate it with proper data.
The issue is I am able to get "securityContent" element using below code and node holds total count of child elements that is 4:
var node = xmlDoc.SelectNodes("/serv:message/header/securityContext/*", GetNameSpace(xmlDoc.NameTable));
But when I try to get another node i.e. "metaData" then I get Count 0 and way to getting element is exactly same except the path to the element.
Below is sample code that I've tried but not working:
static void Main(string[] args)
{
var xmlPathh = #"C:\Users\SKMEENA\Desktop\VILT.xml";// this holds above xml
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(xmlPathh);
var node = xmlDoc.SelectNodes("/serv:message/header/securityContext/*", GetNameSpace(xmlDoc.NameTable));
var member = xmlDoc.SelectNodes("/serv:message/body/bodyContent/metaData/*", GetNameSpace(xmlDoc.NameTable));
}
static XmlNamespaceManager GetNameSpace(XmlNameTable objNameTable)
{
XmlNamespaceManager objNsManager =new XmlNamespaceManager(objNameTable);
objNsManager.AddNamespace("serv", "http://www.webex.com/schemas/2002/06/service");
objNsManager.AddNamespace("ns1", "http://www.webex.com/schemas/2002/06/service/site");
return objNsManager;
}
Anybody has any idea what is wrong with above code and how can I make it working?
The bodyContent node has a default namespace which applies to it and all its children.
You need to add it to the NamespaceManager and then use it in the XPath
var member = xmlDoc.SelectSingleNode("/serv:message/body/body:bodyContent/body:metaData", GetNameSpace(xmlDoc.NameTable));
member.OuterXml.Dump();
static XmlNamespaceManager GetNameSpace(XmlNameTable objNameTable)
{
XmlNamespaceManager objNsManager =new XmlNamespaceManager(objNameTable);
objNsManager.AddNamespace("serv", "http://www.webex.com/schemas/2002/06/service");
objNsManager.AddNamespace("ns1", "http://www.webex.com/schemas/2002/06/service/site");
objNsManager.AddNamespace("body", "http://www.webex.com/schemas/2002/06/service/training");
objNsManager.AddNamespace("sess","http://www.webex.com/schemas/2002/06/session");
return objNsManager;
}
dotnetfiddle
I'm doing a HttpWebrequest by using c#. I get the following response
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Siri version="1.0" xmlns="http://www.siri.org.uk/">
<ServiceDelivery>
<ResponseTimestamp>2013-03-21T11:40:13.514Z</ResponseTimestamp>
<StopMonitoringDelivery version="1.0">
<ResponseTimestamp>2013-03-21T11:40:13.514Z</ResponseTimestamp>
<RequestMessageRef>12345</RequestMessageRef>
<MonitoredStopVisit>
<RecordedAtTime>2013-03-21T11:40:13.514Z</RecordedAtTime>
<MonitoringRef>020035811</MonitoringRef>
<MonitoredVehicleJourney>
<FramedVehicleJourneyRef>
<DataFrameRef>-</DataFrameRef>
<DatedVehicleJourneyRef>-</DatedVehicleJourneyRef>
</FramedVehicleJourneyRef>
<VehicleMode>bus</VehicleMode>
<PublishedLineName>1</PublishedLineName>
<DirectionName>Kempston</DirectionName>
<OperatorRef>STB</OperatorRef>
<MonitoredCall>
<AimedDepartureTime>2013-03-21T11:41:00.000Z</AimedDepartureTime>
<ExpectedDepartureTime>2013-03-21T11:44:27.000Z</ExpectedDepartureTime>
</MonitoredCall>
</MonitoredVehicleJourney>
</MonitoredStopVisit>
</StopMonitoringDelivery>
</ServiceDelivery>
</Siri>
This response is saved in a string variable called "ResponseFromServer"
Now I just want to show the 'ExpectedDepartureTime' in a listbox
I tried to do this with the following code:
//XMLResponse put in documentRoot
XDocument documentRoot = XDocument.Parse(responseFromServer);
//Linq To XML
var documents =
(from docs in documentRoot.Descendants("ServiceDelivery").Descendants("StopMonitoringDelivery").Descendants("MonitoredStopVisit").Descendants("MonitoredVehicleJourney").Descendants("MonitoredCall")
select new
{
dep = docs.Element("ExpectedDepartureTime").Value
});
//Show every ExpectedDepartureTime
foreach (var i in documents)
{
lstHours.Items.Add(i);
MessageBox.Show(i.ToString());
}
When I try this nothing happens (the messagebox is not appearing and in the listbox i see nothnig). I also try to Descendant first the tag without success...
Can anybody help me with this issue?
Thanks!
You need to specify namespace like this and then use one method Descendants
XNamespace ns = "http://www.siri.org.uk/";
var documents =
documentRoot.Descendants(ns + "MonitoredCall")
.Select(x => x.Element(ns + "ExpectedDepartureTime").Value);
now you can
foreach (var i in documents)
{
lstHours.Items.Add(i);
MessageBox.Show(i.ToString());
}
prints
2013-03-21T11:44:27.000Z
I made a request to a third party API and it gives me the following response in XML.
<?xml version="1.0" ?>
<abc>
<xyz>
<code>-112</code>
<message>No such device</message>
</xyz>
</abc>
I read this using this code.
XmlDocument doc = new XmlDocument();
doc.Load("*** url ***");
XmlNode node = doc.SelectSingleNode("/abc/xyz");
string code = node.SelectSingleNode("code").InnerText;
string msg = node.SelectSingleNode("message").InnerText;
Response.Write("Code: " + code);
Response.Write("Message: "+ msg);
But I get an error on this line:
string code = node.SelectSingleNode("code").InnerText;
Error is:
Object reference not set to an instance of an object.
I changed the first line of your XML file into:
<?xml version="1.0"?>
to make it valid XML. With this change, your code works for me. Without the change, the parser throws an exception.
You can use LINQ to XML (if confortable):
XDocument doc = XDocument.Load(url);
var selectors = (from elements in doc.Elements("abc").Elements("xyz")
select elements).FirstOrDefault();
string code = selectors.Element("code").Value;
string msg = selectors.Element("message").Value;
As you've given it, there doesn't seem to be anything wrong with your code Edit : Your declaration is wrong, as svinja pointed out, and your xml won't even load into the XmlDocument.
However, I'm guessing that your xml is more complicated, and there is at least one namespace involved, which would cause the select to fail.
It isn't pretty, but what you can do is use namespace agnostic xpath to locate your nodes to avoid using a XmlNamespaceManager:
XmlDocument doc = new XmlDocument();
doc.Load("*** url ***");
XmlNode node = doc.SelectSingleNode("/*[local-name()='abc']/*[local-name()='xyz']");
string code = node.SelectSingleNode("*[local-name()='code']").InnerText;
string msg = node.SelectSingleNode("*[local-name()='message']").InnerText;
Response.Write("Code: " + code);
Response.Write("Message: "+ msg);
Edit - Elaboration
Your code works fine if you correct the declaration to <?xml version="1.0"?>
However, if you introduce namespaces into the mix, your code will fail unless you use namespace managers appropriately.
My agnostic xpath above will also parse an xml document like so:
<?xml version="1.0"?>
<abc xmlns="foo">
<xyz xmlns="bar">
<code xmlns="bas">-112</code>
<message xmlns="xyz">No such device</message>
</xyz>
</abc>
<?xml version="1.0">
<abc>
<xyz>
<code>-112</code>
<message> No such device </message>
</xyz>
</abc>
try to set a list:
XmlNodeList nodeList = root.SelectNodes("/abc/xyz");
then read all the nodes and get their text:
foreach(XmlNode node in nodeList)
{
if(node.Name == "code")
{
string code = node.InnerText;
}
else
if(node.Name == "message")
{
string msg = node.InnerText;
}
}
[XmlRoot("abc")]
public class Entity
{
[XmlElement("xyz")]
public SubEntity SubEntity { get; set; }
}
public class SubEntity
{
[XmlElement("code")]
public string Code { get; set; }
[XmlElement("message")]
public string Message { get; set; }
}
And use standart xmlserializer
var xmlSerializer = new XmlSerializer(typeof(Entity));
var result = xmlSerializer.Deserialize(new XmlTextReader("*** url ***"));
Response.Write("Code: " + result.SubEntity.Code);
Response.Write("Message: "+ result.SubEntity.Message);
I have a xml file to which I want to add predefined namespeces.. Following is the code:
private const string uri = "http://www.w3.org/TR/html4/";
private static readonly List<string> namespaces = new List<string> { "lun" };
public static XElement AddNameSpaceAndLoadXml(string xmlFile) {
var nameSpaceManager = new XmlNamespaceManager(new NameTable());
// add custom namespace to the manager and take the prefix from the collection
namespaces.ToList().ForEach(name => {
nameSpaceManager.AddNamespace(name, string.Concat(uri, name));
});
XmlParserContext parserContext = new XmlParserContext(null, nameSpaceManager, null, XmlSpace.Default);
using (var reader = XmlReader.Create(#xmlFile, null, parserContext)) {
return XElement.Load(reader);
}
}
The problem is that the resulting xml in memory does not show the correct namespaces added. Also, they are not added at the root but are added next to the tag. Xml added below.
In the xml it is showing p3:read_data while should be lun:read_data.
How do i get to add the namespace on the root tag and not get the incorrect name.
Sample Input xml:
<config file-suffix="perf">
<overview-graph title="Top 5 LUN Reads" max-series="5" remove-series="1">
<counters lun:read_data=""/>
</overview-graph>
</config>
Output xml expected:
<config file-suffix="perf" xmlns:lun="http://www.w3.org/TR/html4/lun">
<overview-graph title="Top 5 LUN Reads" max-series="5" remove-series="1">
<counters lun:read_data="" />
</overview-graph>
</config>
Output that is coming using the above code:
<config file-suffix="perf" >
<overview-graph title="Top 5 LUN Reads" max-series="5" remove-series="1">
<counters p3:read_data="" xmlns:p3="http://www.w3.org/TR/html4/lun"/>
</overview-graph>
</config>
I am not sure if there is a better way, but adding the namespace manually seems to work.
using (var reader = XmlReader.Create(#xmlFile, null, parserContext)) {
var newElement = XElement.Load(reader);
newElement.Add(new XAttribute(XNamespace.Xmlns + "lun", string.Concat(uri, "lun")));
return newElement;
}
I don't know offhand a way to generalize this however (obviously you can add the whole set by enumerating it, but outputting only used namespaces might be interesting).
I'm using System.Xml to get attributes from my xml file.
It seems that following code which I found somewhere is able to find nodes correctly however it doesn't recognizes attributes (it's weird because I've created this xml files with System.Xml too):
DataSet task_data = new DataSet("Root");
adapter.Fill(task_data); // MySqlDataAdapter is being used here
task_data.WriteXml(path, XmlWriteMode.WriteSchema);
So I don't know why any other xml which can be found on the internet works and mine which was created with the same module doesn't...
using System;
using System.Xml;
using System.IO;
public class Catalog
{
private XmlDocument xmldoc;
private string path = #"C:\Users\Me\Desktop\task.xml";
public static void Main()
{
Catalog c = new Catalog();
}
public Catalog()
//Constructor
{
FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
xmldoc = new XmlDocument();
xmldoc.Load(fs);
DisplayCatalog();
}
// Method for Displaying the catalog
private void DisplayCatalog()
{
XmlNodeList xmlnode = xmldoc.GetElementsByTagName("task");
Console.WriteLine("Here is the list of catalogs\n\n");
for (int i = 0; i < xmlnode.Count; i++)
{
XmlAttributeCollection xmlattrc = xmlnode[i].Attributes; //HERE IS THE PROBLEM!!!
Console.Write(xmlnode[i].FirstChild.Name);
Console.WriteLine(":\t\t" + xmlnode[i].FirstChild.InnerText);
Console.Write(xmlnode[i].LastChild.Name);
Console.WriteLine(":\t" + xmlnode[i].LastChild.InnerText);
Console.WriteLine();
}
Console.WriteLine("Catalog Finished");
}
//end of class
}
This is the xml you linked to contins no attributes only nodes.
<?xml version="1.0" standalone="yes"?>
<Root>
<task>
<TaskId>1</TaskId>
<TaskDelegatorNote>Presentation</TaskDelegatorNote>
<StartTime>PT10H</StartTime>
<EndTime>PT13H</EndTime>
<TaskEndDate>2011-01-02T00:00:00+00:00</TaskEndDate>
<TaskContractorNote>Done</TaskContractorNote>
<TaskStatus>3</TaskStatus>
<LastModification>Me, 2003-05-15 13:48:59</LastModification>
</task>
<task>
<TaskId>2</TaskId>
<TaskDelegatorNote>It must be done.</TaskDelegatorNote>
<StartTime>PT10H</StartTime>
<EndTime>PT13H</EndTime>
<TaskEndDate>2011-01-02T00:00:00+00:00</TaskEndDate>
<TaskContractorNote />
<TaskStatus>2</TaskStatus>
<LastModification>Admin, 2009-08-04 10:30:49</LastModification>
</task>
</Root>
Here's an xml snippint with a TaskId attribute
<task TaskId = 1>
</task>
To fix this change
Console.Write(xmlattrc[0].Name);
Console.WriteLine(":\t\t" + xmlattrc[0].Value);
to
Console.Write(xmlnode[0].ChildNodes[0].Name);
Console.WriteLine(":\t\t" + xmlnode[0].ChildNodes[0].Value);
Your output would be
Here is the list of catalogs
TaskId:
TaskId: 1
LastModification: Me, 2003-05-15 13:48:59
TaskId:
TaskId: 2
LastModification: Admin, 2009-08-04 10:30:49
Catalog Finished
Press any key to continue . . .
Also you should look at LinqToXML for some other ways of doing projections of your xml nodes