I am trying to parse a complex XML with C#, I am using Linq to do it. Basically, I am doing a request to a server and I get XML, this is the code:
XElement xdoc = XElement.Parse(e.Result);
this.newsList.ItemsSource =
from item in xdoc.Descendants("item")
select new ArticlesItem
{
//Image = item.Element("image").Element("url").Value,
Title = item.Element("title").Value,
Description = this.Strip(item.Element("description").Value).Substring(0, 200).ToString()
}
And this is the XML structure:
<item>
<test:link_id>1282570</test:link_id>
<test:user>SLAYERTANIC</test:user>
<title>aaa</title>
<description>aaa</description>
</item>
How I can access to the property test:link_id for example?
Thanks!
Currently your XML is invalid since the test namespace is not declared, you can declare it like this:
<item xmlns:test="http://foo.bar">
<test:link_id>1282570</test:link_id>
<test:user>SLAYERTANIC</test:user>
<title>aaa</title>
<description>aaa</description>
</item>
Having this you can use XNamespace to qualify the XML element you want with the correct namespace:
XElement xdoc = XElement.Parse(e.Result);
XNamespace test = "http://foo.bar";
this.newsList.ItemsSource = from item in xdoc.Descendants("item")
select new ArticlesItem
{
LinkID = item.Element(test + "link_id").Value,
Title = item.Element("title").Value,
Description = this.Strip(item.Element("description").Value).Substring(0, 200).ToString()
}
To write a query on XML that is in a
namespace, you must use XName objects
that have the correct namespace. For
C#, the most common approach is to
initialize an XNamespace using a
string that contains the URI, then use
the addition operator overload to
combine the namespace with the local
name.
To retrieve the value of the link_id element you will need to declare and use an XML namespace for the test:link element.
Since you did not show the namespace declaration in your example XML, I am going to assume it is declared somewhere elese in the XML document. You need to locate the namespace declaration in the XML ( something like xmlns:test="http://schema.example.org" ) which is often declared in the root of the XML document.
After you know this, you can do the following to retrieve the value of the link_id element:
XElement xdoc = XElement.Parse(e.Result);
XNamespace testNamespace = "http://schema.example.org";
this.newsList.ItemsSource = from item in xdoc.Descendants("item")
select new ArticlesItem
{
Title = item.Element("title").Value,
Link = item.Element(testNamespace + "link_id").Value,
Description = this.Strip(item.Element("description").Value).Substring(0, 200).ToString()
}
See the XNamespace and Namespaces in C#, and How to: Write Queries on XML in Namespaces for further information.
Related
I have a XML file like this:
<?xml version="1.0" encoding="utf-8"?>
<ApplicationConfiguration xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ua="http://opcfoundation.org/UA/2008/02/Types.xsd" xmlns="http://opcfoundation.org/UA/SDK/Configuration.xsd">
<ServerConfiguration>
<SecurityPolicies>
<ServerSecurityPolicy>
<SecurityMode>None_1</SecurityMode>
</ServerSecurityPolicy>
</SecurityPolicies>
</ServerConfiguration>
</ApplicationConfiguration>
What I want is to add more node named ServerSecurityPolicy by code.
Then I use this code:
string docaddress = "D:\\abc.xml";
XDocument doc = XDocument.Load(docaddress);
var root = doc.Root;
var these = root.Descendants().Where(p => p.Name.LocalName == "SecurityPolicies");
XElement addelement = new XElement("ServerSecurityPolicy");
addelement.Add(new XElement("SecurityMode", "None_1"));
foreach (var elem in these)
{
elem.Add(addelement);
}
doc.Save(docaddress);
It actually works, but the newly added node is something like this:
<ServerSecurityPolicy xmlns="">
<SecurityMode>None_1</SecurityMode>
</ServerSecurityPolicy>
I don't want the attribute "xmlns", then I try to delete it by something like this:
var these2 = root.Descendants().Where(p => p.Name.LocalName == "ServerSecurityPolicy");
foreach (var elem in these2)
{
label2.Text += elem.Attribute("xmlns").Name.LocalName;
elem.Attribute("xmlns").Remove();
}
The label2.Text shows "xmlnsxmlnsxmlsn..." so that I think the elem.Attribute("xmlns") has pointed to the attributes I want to delete, but the Remove() not work.
Can you suggest me some ways to delete the attribute or add node without attribute?
Thank you
The reason you're getting an empty attribute - which xmlns="" refers to - is because your document's root node belongs to the namespace xsi. When you're adding a node without a namespace - as you're doing in your example - you're not actually binding it to the xsi namespace.
To make your node part of the root namespace, replace
new XElement("ServerSecurityPolicy")
with
new XElement("ServerSecurityPolicy",
new XAttribute(XNamespace.Xmlns + "xsi", "http://www.w3.org/2001/XMLSchema-instance"))
The problem is that the element you want to create is actually in the http://opcfoundation.org/UA/SDK/Configuration.xsd namespace, which is the default for the document because of this part of the root element:
xmlns="http://opcfoundation.org/UA/SDK/Configuration.xsd"
You can create an element in that namespace easily:
XNamespace configNs = "http://opcfoundation.org/UA/SDK/Configuration.xsd";
var these = root.Descendants(configNs + "ServerSecurityPolicy");
When you add that to your document, you'll find it won't add the xmlns="" part, which was present because you were adding an element without a namespace.
I'd also suggest using the namespace to find elements too:
XNamespace configNs = "http://opcfoundation.org/UA/SDK/Configuration.xsd";
var these = root.Descendants(configNs + "SecurityPolicies");
That's much cleaner than just using the local name, in my view.
Can't get any result in feeds.
feedXML has the correct data.
XDocument feedXML = XDocument.Load(#"http://search.twitter.com/search.atom?q=twitter");
var feeds = from entry in feedXML.Descendants("entry")
select new
{
PublicationDate = entry.Element("published").Value,
Title = entry.Element("title").Value
};
What am I missing?
You need to specify the namespace:
// This is the default namespace within the feed, as specified
// xmlns="..."
XNamespace ns = "http://www.w3.org/2005/Atom";
var feeds = from entry in feedXML.Descendants(ns + "entry")
...
Namespace handling is beautifully easy in LINQ to XML compared with everything other XML API I've ever used :)
You need to specify a namespace on both the Descendents and Element methods.
XDocument feedXML = XDocument.Load(#"http://search.twitter.com/search.atom?q=twitter");
XNamespace ns = "http://www.w3.org/2005/Atom";
var feeds = from entry in feedXML.Descendants(ns + "entry")
select new
{
PublicationDate = entry.Element(ns + "published").Value,
Title = entry.Element(ns + "title").Value
};
If you look at the XML returned by the HTTP request, you will see that it has an XML namespace defined:
<?xml version="1.0" encoding="UTF-8"?>
<feed xmlns="http://www.w3.org/2005/Atom" ...>
<id>tag:search.twitter.com,2005:search/twitter</id>
...
</feed>
XML is just like C#, if you use an element name with the wrong namespace, it is not considered to be the same element! You need to add the required namepsace to your query:
private static string AtomNamespace = "http://www.w3.org/2005/Atom";
public static XName Entry = XName.Get("entry", AtomNamespace);
public static XName Published = XName.Get("published", AtomNamespace);
public static XName Title = XName.Get("title", AtomNamespace);
var items = doc.Descendants(AtomConst.Entry)
.Select(entryElement => new FeedItemViewModel()
new {
Title = entryElement.Descendants(AtomConst.Title).Single().Value,
...
});
The issue is in feedXML.Descendants("entry"). This is returning 0 results
According to the documentation you need to put in a fully qualified XName
I have an xml template (ReportTemplate.xml) with the following:
<Report xmlns:rd="http://schemas.microsoft.com/SQLServer/reporting/reportdesigner" xmlns:cl="http://schemas.microsoft.com/sqlserver/reporting/2010/01/componentdefinition" xmlns="http://schemas.microsoft.com/sqlserver/reporting/2010/01/reportdefinition">
<ReportSections>
<ReportSection>
<Body>
<ReportItems>
<Tablix Name="Tablix1">
<TablixBody>
<TablixColumns>
</TablixColumns>
<TablixRows>
</TablixRows>
</TablixBody>
</Tablix>
</ReportItems>
</Body>
</ReportSection>
</ReportSections>
</Report>
I have created xml snippets (tablixrow.xml) not fully qualified xml documents as such
<TablixRow>
<Height>0.26736in</Height>
</TablixRow>
In my console app I am trying load both files and insert tablixrow code block into the TablixRows node of the parent document
private static XDocument GenerateReport(List<string>fieldnames)
{
//load base template
XDocument report = XDocument.Load("Templates/ReportTemplate.xml");
XNamespace ns = report.Root.Name.Namespace;
//load row template
XDocument tRows = XDocument.Load("Templates/tablixrow.xml");
//and here is where I am stuck
return report;
}
I'm new to linq and I am trying understand how to navigate to the "TablixRows" node and then insert the tRows block of code.
Can anyone provide some points of reference or examples. What I have see thus far always navigated to and ID. I cannot use id's in this schema and need to rely on the node
-cheers
private static XDocument GenerateReport(List<string>fieldnames)
{
XDocument report = XDocument.Load("Templates/ReportTemplate.xml");
XNamespace ns = report.Root.Name.Namespace;
XElement row = XElement.Load("Templates/tablixrow.xml");
// change namespace for loaded xml elements
foreach (var element in row.DescendantsAndSelf())
element.Name = ns + element.Name.LocalName;
var rows = xdoc.Descendants(ns + "TablixRows").Single();
rows.Add(row);
return report;
}
If you will not change namespace for row template xml, then after adding to report document it will have default namespace (which you don't want):
<TablixRows>
<TablixRow xmlns="">
<Height>0.26736in</Height>
</TablixRow>
</TablixRows>
If some of your templates will have attributes, then you need to provide namespace for attributes also.
I have a following XML (part of a .rdl report):
<Report xmlns:rd="http://schemas.microsoft.com/SQLServer/reporting/reportdesigner" xmlns="http://schemas.microsoft.com/sqlserver/reporting/2008/01/reportdefinition">
<DataSources>
<DataSource Name="TMSSharepointDataSource">
<DataSourceReference>TMSSharepointDataSource</DataSourceReference>
<rd:DataSourceID>f06ffa33-238f-4d83-adfe-1eaa8df96e90</rd:DataSourceID>
</DataSource>
</DataSources>
</Report>
I try to parse and read it using following code:
byte[] fileContent = File.ReadAllBytes(#"path");
UTF8Encoding unicode = new UTF8Encoding();
string stringContent = unicode.GetString(fileContent);
XDocument xml = XDocument.Parse(stringContent);
XElement dsNode = xml.Root.Element("DataSources");
I can't figure out why is dsNode always null?
It's a namespace issue... you need to specify the namespace for the DataSources element. Fortunately, LINQ to XML makes this really easy:
XNamespace ns = "http://schemas.microsoft.com/sqlserver/" +
"reporting/2008/01/reportdefinition";
XElement dsNode = xml.Root.Element(ns + "DataSources");
Note the xmlns="http://..." part of the root element, which means that element and all elements below it which don't have an explicit namespace inherit that namespace.
You are probably missing a namespace reference. Your DataSources will inherit the namespace of the Report node and you will need both the namespace and element local name to generate an XName.
Alternatively you can do the following and skip the namespace check:
XElement dsNode =
xml
.Root
.DescendantNodes()
.Where(e => e.Name.LocalName.Equals("DataSources"))
.First();
This will return the first node where the local name is DataSources. In your example this will be the DataSources element.
Also, your loading of the document is very clumsy. I would suggest the following instead:
XDocument xml = XDocument.Load(File.OpenRead(#"path"));
I'm trying to parse results from the YouTube API. I'm getting the results correctly as a string, but am unable to parse it correctly.
I followed suggestions on a previous thread, but am not getting any results.
My sample code is:
string response = youtubeService.GetSearchResults(search.Term, "published", 1, 50);
XDocument xDoc = XDocument.Parse(response, LoadOptions.SetLineInfo);
var list = xDoc.Descendants("entry").ToList();
var entries = from entry in xDoc.Descendants("entry")
select new
{
Id = entry.Element("id").Value,
Categories = entry.Elements("category").Select(c => c.Value)
//Published = entry.Element("published").Value,
//Title = entry.Element("title").Value,
//AuthorName = entry.Element("author").Element("name").Value,
//Thumnail = entry.Element("media:group").Elements("media:thumnail").ToList().ElementAt(0)
};
foreach (var entry in entries)
{
// entry.Id and entry.Categories available here
}
The problem is that entries has a count of 0 even though the XDocument clearly has the valid values.
The value of the response variable (Sample XML) can be seen here: http://snipt.org/lWm
(FYI: The youTube schema is listed here: http://code.google.com/apis/youtube/2.0/developers_guide_protocol_understanding_video_feeds.html)
Can anyone tell me what I'm doing wrong here?
All the data is in the "http://www.w3.org/2005/Atom" namespace; you need to use this throughout:
XNamespace ns = XNamespace.Get("http://www.w3.org/2005/Atom");
...
from entry in xDoc.Descendants(ns + "entry")
select new
{
Id = entry.Element(ns + "id").Value,
Categories = entry.Elements(ns + "category").Select(c => c.Value)
...
};
etc (untested)
When you see prefix:name, it means that name is in the namespace whose prefix has been declared as prefix. If you look at the top of the document, you'll see an xmlns:media=something. The something is the namespace used for anything with the prefix media.
This means you need to create an XNamespace for each of the namespaces you need to reference:
XNamespace media = XNamespace.Get("http://search.yahoo.com/mrss/");
and then use media for the names in that namespace:
media + "group"
The namespaces in this document are:
xmlns="http://www.w3.org/2005/Atom"
xmlns:app="http://www.w3.org/2007/app"
xmlns:media="http://search.yahoo.com/mrss/"
xmlns:openSearch="http://a9.com/-/spec/opensearch/1.1/"
xmlns:gd="http://schemas.google.com/g/2005"
xmlns:gml="http://www.opengis.net/gml"
xmlns:yt="http://gdata.youtube.com/schemas/2007"
xmlns:georss="http://www.georss.org/georss"
You need to set the namespace.
Creating an XName in a Namespace
As with XML, an XName can be in a namespace, or it can be in no namespace.
For C#, the recommended approach for creating an XName in a namespace is to declare the XNamespace object, then use the override of the addition operator.
http://msdn.microsoft.com/en-us/library/system.xml.linq.xname.aspx