Consider generating the following XML structure, which has 2 prefixed namespaces:
XNamespace ns1 = "http://www.namespace.org/ns1";
const string prefix1 = "w1";
XNamespace ns2 = "http://www.namespace.org/ns2";
const string prefix2 = "w2";
var root =
new XElement(ns1 + "root",
new XElement(ns1 + "E1"
, new XAttribute(ns1 + "attr1", "value1")
, new XAttribute(ns2 + "attr2", "value2"))
, new XAttribute(XNamespace.Xmlns + prefix2, ns2)
, new XAttribute(XNamespace.Xmlns + prefix1, ns1)
);
It generates the following XML result (which is fine):
<w1:root xmlns:w2="http://www.namespace.org/ns2" xmlns:w1="http://www.namespace.org/ns1">
<w1:E1 w1:attr1="value1" w2:attr2="value2" />
</w1:root>
The problem arises when I try to change ns1 from a prefixed namespace to a default namespace by commenting out its XML declaration, as in:
var root =
new XElement(ns1 + "root",
new XElement(ns1 + "E1"
, new XAttribute(ns1 + "attr1", "value1")
, new XAttribute(ns2 + "attr2", "value2"))
, new XAttribute(XNamespace.Xmlns + prefix2, ns2)
//, new XAttribute(XNamespace.Xmlns + prefix1, ns1)
);
which produces:
<root xmlns:w2="http://www.namespace.org/ns2" xmlns="http://www.namespace.org/ns1">
<E1 p3:attr1="value1" w2:attr2="value2" xmlns:p3="http://www.namespace.org/ns1" />
</root>
Note the duplicate namespace definitions in root and E1 and attributes prefixed as p3 under E1. How can I avoid this from happening? How can I force declaration of default namespace in the root element?
Related Questions
I studied this question: How to set the default XML namespace for an XDocument
But the proposed answer replaces namespace for elements without any namespace defined. In my samples the elements and attributes already have their namespaces correctly set.
What I have tried
Based on too many trial and errors, it seems to me that attributes which are not directly under the root node, where the attribute and its direct parent element both have the same namespace as the default namespace; the namespace for the attribute needs to be removed!!!
Based on this I defined the following extension method which traverses all the elements of the resulting XML and performs the above. In all my samples thus far this extension method fixed the problem successfully, but it doesn't necessarily mean that somebody can't produce a failing example for it:
public static void FixDefaultXmlNamespace(this XElement xelem, XNamespace ns)
{
if(xelem.Parent != null && xelem.Name.Namespace == ns)
{
if(xelem.Attributes().Any(x => x.Name.Namespace == ns))
{
var attrs = xelem.Attributes().ToArray();
for (int i = 0; i < attrs.Length; i++)
{
var attr = attrs[i];
if (attr.Name.Namespace == ns)
{
attrs[i] = new XAttribute(attr.Name.LocalName, attr.Value);
}
}
xelem.ReplaceAttributes(attrs);
}
}
foreach (var elem in xelem.Elements())
elem.FixDefaultXmlNamespace(ns);
}
This extension method produces the following XML for our question, which is what I desire:
<root xmlns:w2="http://www.namespace.org/ns2" xmlns="http://www.namespace.org/ns1">
<E1 attr1="value1" w2:attr2="value2" />
</root>
However I don't like this solution, mainly because it is expensive. I feel I'm missing a small setting somewhere. Any ideas?
Quoting from here:
An attribute is not considered a child of its parent element. 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. An attribute can never be in a default namespace.
and here:
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.
It seems that this odd behavior of LINQ-to-XML is rooted in standards. Therefore whenever adding a new attribute its namespace must be compared against the parents' default namespace which is active in its scope. I use this extension method for adding attributes:
public static XAttribute AddAttributeNamespaceSafe(this XElement parent,
XName attrName, string attrValue, XNamespace documentDefaultNamespace)
{
if (newAttrName.Namespace == documentDefaultNamespace)
attrName = attrName.LocalName;
var newAttr = new XAttribute(attrName, attrValue);
parent.Add(newAttr);
return newAttr;
}
And use this extension method for retrieving attributes:
public static XAttribute GetAttributeNamespaceSafe(this XElement parent,
XName attrName, XNamespace documentDefaultNamespace)
{
if (attrName.Namespace == documentDefaultNamespace)
attrName = attrName.LocalName;
return parent.Attribute(attrName);
}
Alternatively, if you have the XML structure at hand and want to fix the namespaces already added to attributes, use the following extension method to fix this (which is slightly different from that outlined in the question):
public static void FixDefaultXmlNamespace(this XElement xelem,
XNamespace documentDefaultNamespace)
{
if (xelem.Attributes().Any(x => x.Name.Namespace == documentDefaultNamespace))
{
var attrs = xelem.Attributes().ToArray();
for (int i = 0; i < attrs.Length; i++)
{
var attr = attrs[i];
if (attr.Name.Namespace == documentDefaultNamespace)
{
attrs[i] = new XAttribute(attr.Name.LocalName, attr.Value);
}
}
xelem.ReplaceAttributes(attrs);
}
foreach (var elem in xelem.Elements())
elem.FixDefaultXmlNamespace(documentDefaultNamespace);
}
Note that you won't need to apply the above method, if you have used the first two methods upon adding and retrieving attributes.
I have found something for you, from the C# in a Nutshell book:
You can assign namespaces to attributes too. The main difference is that it always
requires a prefix. For instance:
<customer xmlns:nut="OReilly.Nutshell.CSharp" nut:id="123" />
Another difference is that an unqualified attribute always has an empty namespace:
it never inherits a default namespace from a parent element.
So given your desired output i have made a simple check.
var xml = #"<root xmlns:w2=""http://www.namespace.org/ns2"" xmlns=""http://www.namespace.org/ns1"">
<E1 attr1=""value1"" w2:attr2=""value2"" />
</root>";
var dom = XElement.Parse(xml);
var e1 = dom.Element(ns1 + "E1");
var attr2 = e1.Attribute(ns2 + "attr2");
var attr1 = e1.Attribute(ns1 + "attr1");
// attr1 is null !
var attrNoNS = e1.Attribute("attr1");
// attrNoNS is not null
So in short attr1 does not have default namespace, but has an empty namespace.
Is this you want? If yes, just create you attr1 without namespace...
new XAttribute("attr1", "value1")
Related
How can I remove the xmlns namespace from a XElement?
I tried: attributes.remove, xElement.Name.NameSpace.Remove(0), etc, etc. No success.
My xml:
<event xmlns="http://www.blablabla.com/bla" version="1.00">
<retEvent version="1.00">
</retEvent>
</event>
How can I accomplish this?
#octaviocc's answer did not work for me because xelement.Attributes() was empty, it wasn't returning the namespace as an attribute.
The following will remove the declaration in your case:
element.Name = element.Name.LocalName;
If you want to do it recursively for your element and all child elements use the following:
private static void RemoveAllNamespaces(XElement element)
{
element.Name = element.Name.LocalName;
foreach (var node in element.DescendantNodes())
{
var xElement = node as XElement;
if (xElement != null)
{
RemoveAllNamespaces(xElement);
}
}
}
I'd like to expand upon the existing answers. Specifically, I'd like to refer to a common use-case for removing namespaces from an XElement, which is: to be able to use Linq queries in the usual way.
When a tag contains a namespace, one has to use this namespace as an XNamespace on every Linq query (as explained in this answer), so that with the OP's xml, it would be:
XNamespace ns = "http://www.blablabla.com/bla";
var element = xelement.Descendants(ns + "retEvent")).Single();
But usually, we don't want to use this namespace every time. So we need to remove it.
Now, #octaviocc's suggestion does remove the namespace attribute from a given element. However, the element name still contains that namespace, so that the usual Linq queries won't work.
Console.WriteLine(xelement.Attributes().Count()); // prints 1
xelement.Attributes().Where( e => e.IsNamespaceDeclaration).Remove();
Console.WriteLine(xelement.Attributes().Count()); // prints 0
Console.WriteLine(xelement.Name.Namespace); // prints "http://www.blablabla.com/bla"
XNamespace ns = "http://www.blablabla.com/bla";
var element1 = xelement.Descendants(ns + "retEvent")).SingleOrDefault(); // works
var element2 = xelement.Descendants("retEvent")).SingleOrDefault(); // returns null
Thus, we need to use #Sam Shiles suggestion, but it can be simplified (no need for recursion):
private static void RemoveAllNamespaces(XElement xElement)
{
foreach (var node in xElement.DescendantsAndSelf())
{
node.Name = node.Name.LocalName;
}
}
And if one needs to use an XDocument:
private static void RemoveAllNamespaces(XDocument xDoc)
{
foreach (var node in xDoc.Root.DescendantsAndSelf())
{
node.Name = node.Name.LocalName;
}
}
And now it works:
var element = xelement.Descendants("retEvent")).SingleOrDefault();
You could use IsNamespaceDeclaration to detect which attribute is a namespace
xelement.Attributes()
.Where( e => e.IsNamespaceDeclaration)
.Remove();
Before posting this question I have tried all other solution on stack, but with no success.
I am unable to remove empty xmlns attribute from XElement using C#, I have tried the following Codes.
XElement.Attributes().Where(a => a.IsNamespaceDeclaration).Remove();
Another one which postted here
foreach (var attr in objXMl.Descendants().Attributes())
{
var elem = attr.Parent;
attr.Remove();
elem.Add(new XAttribute(attr.Name.LocalName, attr.Value));
}
Image This is you xml file
<Root xmlns="http://my.namespace">
<Firstelement xmlns="">
<RestOfTheDocument />
</Firstelement>
</Root>
This is you expect
<Root xmlns="http://my.namespace">
<Firstelement>
<RestOfTheDocument />
</Firstelement>
</Root>
I think the code below is what you want. You need to put each element into the right namespace, and remove any xmlns='' attributes for the affected elements. The latter part is required as otherwise LINQ to XML basically tries to leave you with an element of
<!-- This would be invalid -->
<Firstelement xmlns="" xmlns="http://my.namespace">
Here's the code:
using System;
using System.Xml.Linq;
class Test
{
static void Main()
{
XDocument doc = XDocument.Load("test.xml");
foreach (var node in doc.Root.Descendants())
{
// If we have an empty namespace...
if (node.Name.NamespaceName == "")
{
// Remove the xmlns='' attribute. Note the use of
// Attributes rather than Attribute, in case the
// attribute doesn't exist (which it might not if we'd
// created the document "manually" instead of loading
// it from a file.)
node.Attributes("xmlns").Remove();
// Inherit the parent namespace instead
node.Name = node.Parent.Name.Namespace + node.Name.LocalName;
}
}
Console.WriteLine(doc); // Or doc.Save(...)
}
}
If you add the namespace of the parent element to the element then the empty namespace tag disappears, as it isn't required because the element is in the same namespace.
here's a simpler way to do this. I believe it happens when you create separate xml segments and then join them to your document.
xDoc.Root.SaveDocument(savePath);
private static void SaveDocument(this XElement doc, string filePath)
{
foreach (var node in doc.Descendants())
{
if (node.Name.NamespaceName == "")
{
node.Name = ns + node.Name.LocalName;
}
}
using (var xw = XmlWriter.Create(filePath, new XmlWriterSettings
{
//OmitXmlDeclaration = true,
//Indent = true,
NamespaceHandling = NamespaceHandling.OmitDuplicates
}))
{
doc.Save(xw);
}
}
Did you try to get Xelement.Attribute by value to see if the element is the "xmlns" before removing.
Xelement.Attribute("xmlns").Value
I have a code which will read some xml file(s). I tried different ways to solve this problem, but couldn't. Also I tried to code like this:
Namespace my = "http://schemas.microsoft.com/office/infopath/2003/myXSD/2011-01-11T08:31:30";
XElement myEgitimBilgileri = XDocument.Load(#"C:\25036077.xml").Element("my:"+ "Egitim_Bilgileri");
But all the time the same mistake. Here is the original:
private void button2_Click(object sender, EventArgs e)
{
XElement myEgitimBilgileri =
XDocument.Load(#"C:\25036077.xml").Element("my:Egitim_Bilgileri");
if (myEgitimBilgileri != null)
{
foreach (XElement element in myEgitimBilgileri.Elements())
{
Console.WriteLine("Name: {0}\tValue: {1}", element.Name, element.Value.Trim());
}
}
Console.Read();
}
Here is a path of my xml file:
<my:Egitim_Bilgileri>
<my:egitimler_sap>
<my:sap_eduname></my:sap_eduname>
<my:sap_edufaculty></my:sap_edufaculty>
<my:sap_eduprofession></my:sap_eduprofession>
<my:sap_diplomno></my:sap_diplomno>
<my:sap_edulevel></my:sap_edulevel>
<my:sap_edustartdate xsi:nil="true"></my:sap_edustartdate>
<my:sap_eduenddate xsi:nil="true"></my:sap_eduenddate>
</my:egitimler_sap>
</my:Egitim_Bilgileri>
and this is the path of my namespace in XML
xmlns:my="http://schemas.microsoft.com/office/infopath/2003/myXSD/2011-01-11T08:31:30"
xmlns:my="http://schemas.microsoft.com/office/infopath/2003/myXSD/2008-01-23T00:43:17"
The code Element("my:" + "Egitim_Bilgileri") is the same as Element("my:Egitim_Bilgileri") which is taken to mean the element named "my:Egitim_Bilgileri" in the default namespace (there is an implicit conversion from string to XName).
However, : is invalid in an element name (outside of the namespace separation) and thus will result in a run-time exception.
Instead, the code should be Element(my + "Egitim_Bilgileri") where my is an XNamespace object. The XNamespace object's + operator, when given a string as the second operand, results in an XName object that can then be used with the Element(XName) method.
For instance:
XNamespace my = "http://schemas.microsoft.com/office/infopath/2003/myXSD/2011-01-11T08:31:30";
XDocument doc = XDocument.Load(#"C:\25036077.xml");
// The following variable/assignment can be omitted,
// it is to show the + operator of XNamespace and how it results in XName
XName nodeName = my + "Egitim_Bilgileri";
XElement myEgitimBilgileri = doc.Element(nodeName);
Happy coding... and condolences for having to deal with InfoPath :)
I prefer to use XPath in most cases. Among other things it allows easily selecting nested nodes and avoids having to "check for null" each level as may be required with node.Element(x).Element(y) constructs.
using System.Xml.XPath; // for XPathSelectElement extension method
XmlNamespaceManager ns = new XmlNamespaceManager(new NameTable());
ns.AddNamespace("my", "http://schemas.microsoft.com/office/infopath/2003/myXSD/2011-01-11T08:31:30")
// Note that there is no XName object. Instead the XPath string is parsed
// and namespace resolution happens via the XmlNamespaceManager
XElement myEgitimBilgileri = doc.XPathSelectElement("/my:myFields/my:Egitim_Bilgileri", ns);
I'm using LINQ to XML to generate a piece of XML. Everything works great except I'm throwing in some empty namespace declarations somehow. Does anyone out there know what I'm doing incorrectly? Here is my code
private string SerializeInventory(IEnumerable<InventoryInformation> inventory)
{
var zones = inventory.Select(c => new {
c.ZoneId
, c.ZoneName
, c.Direction
}).Distinct();
XNamespace ns = "http://www.dummy-tmdd-address";
XNamespace xsi = "http://www.w3.org/2001/XMLSchema-instance";
var xml = new XElement(ns + "InventoryList"
, new XAttribute(XNamespace.Xmlns + "xsi", xsi)
, zones.Select(station => new XElement("StationInventory"
, new XElement("station-id", station.ZoneId)
, new XElement("station-name", station.ZoneName)
, new XElement("station-travel-direction", station.Direction)
, new XElement("detector-list"
, inventory.Where(p => p.ZoneId == station.ZoneId).Select(plaza =>
new XElement("detector", new XElement("detector-id", plaza.PlazaId)))))));
xml.Save(#"c:\tmpXml\myXmlDoc.xml");
return xml.ToString();
}
And here is the resulting xml. I hope it renders correctly? The browser may hide the tags.
<InventoryList xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.dummy-tmdd-address">
<StationInventory xmlns="">
<station-id>999</station-id>
<station-name>Zone 999-SEB</station-name>
<station-travel-direction>SEB</station-travel-direction>
<detector-list>
<detector>
<detector-id>7503</detector-id>
</detector>
<detector>
<detector-id>2705</detector-id>
</detector>
</detector-list>
</StationInventory>
</InventoryList>
Notice the empty namespace declaration in the first child element. Any ideas how I can remedy this? Any tips are of course appreciated.
Thanks All.
Because of the missing namespace in:
new XElement("StationInventory"...
This implicitly indicates the empty namespace "" for the StationInvetory element. You should do:
new XElement(ns + "StationInventory"...
Note that you must do this for any element you create that lives in the ns namespace. The XML serializer will make sure to qualify elements with the correct namespace prefix according to scope.
Want to add to Peter Lillevold's answer.
XML Attributes don't require namespase in their XName
In addition to casting string to Xname:
The {myNamespaseName} will be casted to XNamespase on casting of "{myNamespaseName}nodeName" to XName
Also, look to the code structure that simplifies reading of the constructor method:
private readonly XNamespace _defaultNamespace = "yourNamespace";
public XElement GetXmlNode()
{
return
new XElement(_defaultNamespace + "nodeName",
new XElement(_defaultNamespace + "nodeWithAttributes",
new XAttribute("attribute1Name", "valueOfAttribute1"),
new XAttribute("attribute2Name", "valueOfAttribute2"),
"valueOfnodeWithAttributes"
)
);
}
or
public XElement GetXmlNode()
{
return
new XElement("{myNamespaseName}nodeName",
new XElement("{myNamespaseName}nodeWithAttributes",
new XAttribute("attribute1Name", "valueOfAttribute1"),
new XAttribute("attribute2Name", "valueOfAttribute2"),
"valueOfnodeWithAttributes"
)
);
}
I have the following method to parse XMLElements:
DisplayMessages(XElement root)
{
var items = root.Descendants("Item");
foreach (var item in items)
{
var name = item.Element("Name");
....
}
}
In debug mode, I can see the root as XML like this:
<ItemInfoList>
<ItemInfo>
<Item>
<a:Name>item 1</a:Name>
...
<Item>
...
and var name is null (I expect to get "item 1"). I tried to use "a:Name" but it caused exception("character : cannot be used in name"). I am not sure if I have to set namespace in root XElelement or not. All the xml node under root should be in the same namespace.
I am new to XElement. In my codes, item.Element("Name") will get its children node "Name"'s value value, is that right?
You need to use element names that include namespace. Try this:
static void DisplayMessages(XElement root)
{
var items = root.Descendants(root.GetDefaultNamespace() + "Item");
foreach (var item in items)
{
var name = item.Element(item.GetNamespaceOfPrefix("a") + "Name");
Console.WriteLine(name.Value);
}
}
Note that operator + is overloaded for XNamespace class in order to make code shorter: XNamespace.Addition Operator.
You do need to define the "a" namespace in the root element:
<Root a:xmlns="http:///someuri.com">
...
</Root>
Then you can select an element in a non-default namespace using this syntax in LINQ to XML:
XNamespace a = "http:///someuri.com"; // must match declaration in document
...
var name = item.Element(a + "Name");
EDIT:
To retrieve the default namespace:
XNamespace defaultNamespace = document.Root.GetDefaultNamespace();
// XNamespace.None is returned when default namespace is not explicitly declared
To find other namespace declarations:
var declarations = root.Attributes().Where(a => a.IsNamespaceDeclaration);
Note that namespaces can be declared on any element though so you would need to recursively search all elements in a document to find all namespace declarations. In practice though this is generally done in the root element, if you can control how the XML is generated then that won't be an issue.
You need to create XNames that have a non-null Namespace. To do so, you have to create an XNamespace, and add the element name, see Creating an XName in a Namespace.
If you work with XML data that contains namespaces, you need to declare these namespaces. (That's a general observation I made, even though it seems to make it difficult to "just have a look" on data you don't know).
You need to declare an XNamespace for your XElements, as in these MSDN samples: Element(), XName