Suppose I have such elements in my XML document:
<xs:appinfo>
<CustomXML>
<Something>something</Something>
</CustomXML>
</xs:appinfo>
"xs" is declared as the default schema namespace. My question is: how would a parser interpret the inner elements of xs:appinfo? In which namespace do they belong?
I ask because I'm parsing the code in C# and it keeps adding "xmlns="" " to the CustomXML element, which makes me assume that otherwise it'd treat these elements as schema elements.
According to §6.2 Namespace Defaulting of Namespaces in XML 1.0 (Third Edition):
The scope of a default namespace declaration extends from the beginning of the start-tag in which it appears to the end of the corresponding end-tag, excluding the scope of any inner default namespace declarations. […]
A default namespace declaration applies to all unprefixed element names within its scope.
That means that elements with no namespace prefix are interpreted as being in the default namespace. Default namespace is usually defined on the first element of the document and look like this:
<element xmlns="namespace-uri">
The library redefines the default namespace when it's necessary, that is, when you add an element to the document with no namespace. In other words, such element is not in the default namespace, so the library solves this by adding xmlns="" to that element, which redefined the default namespace for this element and all its descendants to "no namespace".
If you want to add element that is in the default namespace, you have to specify it explicitly. For example, in LINQ to XML:
XDocument doc = …;
var ns = doc.Root.GetDefaultNamespace();
var newElement = new XElement(ns + "foo"));
Related
I need to produce an xml document where all elements and attributes are prefixed with (the same) namespace (I know this is not ideal, but unfortunately is needed for interoperation with InfoPath). Using the .NET XmlSerializer, initialized with the right namepsace and prefix, I generally have no problem generating prefixed xml:
xmlSerializer = new XmlSerializer(typeof(T));
xmlNamespaces = new XmlSerializerNamespaces();
xmlNamespaces.Add("foo", "www.namespace.com");
...
[XmlRoot(Namespace = "www.namespace.com")]
public class label
{
[XmlAttribute(Namespace = "www.namespace.com")]
public string id { get; set; }
[XmlElement(Namespace = "www.namespace.com")]
public string text { get; set; }
}
This generates xml
<foo:label id="0" xmlns:foo="www.namespace.com">
<foo:text>content</foo:text>
</foo:label>
The problem is this: the prefix is applied to everything, except the "id" attribute in the same namespace.
I thought this might be behavior prescribed by W3C, and that attributes declared as belonging to a prefixed element would inherit that prefix. However, it seems that attributes that do not have an associated namespace/prefix do not behave like this - see XML namespaces and attributes and here, which states:
"An attribute never inherits the namespace of its parent element. For that reason an attribute is only in a namespace if it has a proper namespace prefix"
In this case, shouldn't the serializer generate a prefix to show the attribute is in that namespace? Or is this not correct?
Thanks in advance!
MORE INFO: Further investigation (see SamuelNeff's answer below) has determined that unprefixed attributes do not inherit the namespace of their containing element. Does this mean the XmlSerializer is producing off-spec attributes? Is there a way to force it to add the prefix? It will add a prefix if a different namespace uri is added in the XmlAttribute attribute.
OOPS: My interpretation of spec is wrong. This incorrect response is marked as the answer, so I can't delete it. Sorry.
Attributes without prefixes are in the same namespace as their containing element. You only need to apply a prefix to an attribute if the attribute has a namespace different from its element.
Default namespace declarations do not apply directly to attribute names; the interpretation of unprefixed attributes is determined by the element on which they appear.
http://www.w3.org/TR/2009/REC-xml-names-20091208/#defaulting
Try using the Prefix property?
XmlAttribute Prefix on MSDN
This is a rather odd problem, also setting the Prefix and NamespaceURI manually is probably error prone. Are you sure the namespace on the attribute is even necessary? While it may not be to spec, the client or server you are working with should skip the containing element of the attribute if it is in your foo namespace right? At which point why would it care what namespace your attribute has.
I know how I can create a new XML file, set the declaration, the name space and add new elements to the root. However, if I want to append elements to an existing file it is added xmlns as attribute of the new element:
<NewElement p3:id="1" idAux="A1" xmlns:p3="http://xyz.com/2006/bbb" xmlns="">
I try to use the loaded the namespace of the document, but that does not work.
How can I add new elements to an existing file and respect the format of the existing elements?
I am using linq to xml.
Thanks.
Try the following code:
// Assume 'el' is the new element that's created.
XElement el = new XElement("NewElement", new XAttribute("{p3}id", 1), new XAttribute("idAux", "A1"));
The above should create the following:
<NewElement p3:id="1" idAux="A1">
Note that the namespace p3 may be created on the document root element--I'm not sure about that. Also I know that with the old System.Xml API, if you didn't specify a default namespace for your document, then the XmlSerializer would add the xsi and xsd namespaces automatically.
I know in the old Xml API, the correct way to specify a default namespace was to add a XmlNamespaceManager-type property to your class (which is a container for an array of XmlQualifiedName objects) and add a XmlQualifiedName object as follows: new XmlQualifiedName(string.Empty, "urn:your-namespace-name"). You probably need to do something similar for your document using XML-to-LINQ.
I have a SO post about that: XmlSerializer: remove unnecessary xsi and xsd namespaces. HTH.
I have an XPath query which looks right to me, but isn't returning any results.
The XML document it's being tested against:
<Deployment xmlns="http://schemas.microsoft.com/client/2007/deployment" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Deployment.Parts>
<AssemblyPart x:Name="foo" Source="foo.dll" />
</Deployment.Parts>
</Deployment>
The code:
Xml = new XmlDocument();
Xml.LoadXml(text);
Manager = new XmlNamespaceManager(Xml.NameTable);
//use constants for namespaces to make more readable
Manager.AddNamespace("a", NS_DEPLOYMENT_2007); //use 'a' for default namespace here so xpath is easier
Manager.AddNamespace("x", NS_XAML_2006);
string xpath="//a:Deployment.Parts/a:AssemblyPart[#a:Source='foo.dll']";
var tmp = Xml.SelectNodes(xpath, Manager);
What is wrong with my XPath query here?
You need to remove the namespace prefix from your attribute:
string xpath="//a:Deployment.Parts/a:AssemblyPart[#Source='foo.dll']";
You only need to specify the namespace for the attribute if it explicitly has a namespace defined, so when you would want to query the Name attribute, you would have to add it:
string xpath="//a:Deployment.Parts/a:AssemblyPart[#x:Name='foo']";
I suspect this part is your problem:
#a:Source='foo.dll'
Unlike element names, attribute names don't inherit a namespace. Your document doesn't specify a namespace for the attribute, so I don't think you should do so either.
Try just:
#Source='foo.dll'
(As an aside, I would personally use LINQ to XML instead of XPath - I find it generally simpler. YMMV, but it may be worth considering - if you're using .NET 3.5 or higher, of course.)
From "Namespaces in XML 1.0 (3rd edition)" section 6.2 (emphasis mine):
The scope of a default namespace declaration extends from the beginning of the start-tag in which it appears to the end of the corresponding end-tag, excluding the scope of any inner default namespace declarations. In the case of an empty tag, the scope is the tag itself.
A default namespace declaration applies to all unprefixed element names within its scope. Default namespace declarations do not apply directly to attribute names; the interpretation of unprefixed attributes is determined by the element on which they appear.
I'm having trouble deserializing XML with an "undefined" namespace prefix which really is defined.
We've published an internal web service in C# which serves a variety of clients. A new client's IDE insists on declaring xsi:type for every element in its XML output, and they can't turn off this "feature".
The XML message they produce goes like this, where "namespace" is the correct namespace.
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<myOperation xsi:type="ns1:namespace" xmlns="namespace" xmlns:ns1="namespace">
<inputString xsi:type="xsd:string">ABCDEF</inputString>
<books xsi:type="ns1:booksType">
<bookID xsi:type="xsd:string">ABC123</bookID>
<bookID xsi:type="xsd:string">DEF456</bookID>
</books>
<!-- ... snip... -->
</myOperation>
</soapenv:Body>
<books> is basically an array of strings.
The service method accepts as XmlNode, but XmlSerializer throws a "prefix 'ns1' not defined" error. (It is defined in a parent node, but apparently that is not good enough.) I have a similar problem using wsdl.exe to generate classes and deserialize the input for me.
Using XmlNamespaceManager to specify prefixes doesn't seem right -- akin to magic numbers, and I can't predict which prefix a given consumer will declare anyway. Is there a way to handle this without stripping the attributes out (books.Attributes.RemoveAll)? That doesn't feel particularly elegant either.
I've found that books.OuterXML does not contain any information for 'ns1' unless I hack the element inbound to use that prefix (), so I can see why it complains, but I don't yet understand why 'ns1' isn't recognized from its previous definition above.
Many thanks for any help, or at least education, someone can provide.
Edits: it works fine if I change <books> to use the prefix, i.e. <ns1:books xsi:type="ns1:booksType">. This works whether I've defined xmlns or no. That may be consistent with this answer, but I still don't see how I would feasibly declare the prefix in the service code.
#Chris, certainly. Hope I can strike a balance between "stingy with closed source" and "usable for those who would help". Here "books" is the XmlNode received in the service method parameter. (Not to get off topic, but will also humbly take suggestions to improve it in general; I'm still a novice.)
XmlSerializer xmlSerializer = new XmlSerializer(typeof(booksType));
StringReader xmlDataReader = new StringReader(books.OuterXml);
books = (booksType)xmlSerializer.Deserialize(xmlDataReader);
The class is pretty much this:
[Serializable()]
[XmlRoot("books", Namespace = "namespace")]
[XmlTypeAttribute(TypeName = "booksType", Namespace = "namespace")]
public class booksType
{
[XmlElement(ElementName = "bookID")]
public string[] bookIDs { get; set; }
}
Your deserialization code could look something like this:
XmlSerializer sz = new XmlSerializer(typeof(booksType));
var reader = new XmlNodeReader(booksXmlNode);
var books = sz.Deserialize(reader);
[EDIT] This is better, because the namespace declarations are preserved with the XmlNode, whereas converting to an XML string via OuterXml appears to slice off the namespace declaration for the ns1 prefix, and the serializer then barfs on the type attribute value containing this prefix. I imagine this is a bug in the XML implementation but maybe an XML guru can confirm this.
This should get you past the error you are seeing, but whether it solves the problem completely I'm not sure.
[FURTHER EDIT] As noted in the comments below, there is a bug in the .NET XmlSerializer which is causing the deserialization to fail. Stepping through the deserialization code in the generated assembly, there is a point where the following condition is tested:
(object) ((System.Xml.XmlQualifiedName)xsiType).Namespace == (object)id2_namespace))
Although the Namespace property of the XmlQualifiedName has the same value ('namespace') as the string variable id2_namespace, the condition is evaluating to false because it is coded as an object identity test rather than a test for string value equivalence. Failing this condition leads directly to the exception reported by OP.
As far as I can see, this bug will always cause deserialization to fail whenever the XML for the object being deserialized uses one prefix on the object's root element name, and another prefix (defined as the same namespace) on that element's xsi:type attribute.
I'd like to write out the following XAML using LINQ to XML via C#.
<Activity x:Class="WorkflowConsoleApplication1.Activity1" mva:VisualBasic.Settings="Assembly references and imported namespaces for internal implementation"> </Activity>
How do I specify the XNamespace for doing this to achieve the above output?
This code will do it:
var el = new XElement(
"Activity",
new XAttribute(XName.Get("Class", "SomeNamespace"), "WorkflowConsoleApplication1.Activity1"),
new XAttribute(
XName.Get("VisualBasic.Settings", "SomeOtherNamespace"),
"Assembly references and imported namespaces for internal implementation"));
Console.WriteLine(el.ToString());
Notice how you do not specify the prefixes, but rather the namespaces that these attributes belong to. This is by design and consistent with the XML spec. Prefixes will be generated automatically, or picked up from the containing element if this element is a child of another element that has already defined a prefix for the namespaces you're using.