Sorry to bother you with such a simple question, but I'm stuck here since an hour:
I have an xml file that looks something like this:
<?xml version="1.0" encoding="utf-8"?>
<aaa xmlns="http://blabla.com/xmlschema/v1">
<bbb>
<ccc>Foo</ccc>
</bbb>
<ddd x="y" />
<ddd x="xx" />
<ddd x="z" />
</aaa>
I'm trying to access the elements 'ddd' like this:
var doc = new XmlDocument();
doc.Load("example.xml");
foreach (XmlNode dddNode in doc.DocumentElement.SelectNodes("//ddd"))
{
// do something
Console.WriteLine(dddNode.Attributes["x"].Value);
}
At runtime the foreach loop is skipped because I don't get any nodes back from the .SelectNodes method. I breaked before the loop and had a look at the InnerXML, that looks fine, and I also tried all sorts of XPaths (like "//bbb" or "/aaa/ddd"), but only "/" seems to not return null.
This exact code worked for me before, now it does not. I suspect something with that namespace declaration in the aaa tag, but I couldn't figure out why this should cause problems. Or.. can you see anything I may be missing?
This is xml-namespaces. There is no ddd. There is, however, x:ddd where x is your alias to http://blabla.com/xmlschema/v1. You'll need to test with namespaces - for example:
var nsmgr = new XmlNamespaceManager(doc.NameTable);
nsmgr.AddNamespace("x", "http://blabla.com/xmlschema/v1");
var nodes = doc.DocumentElement.SelectNodes("//x:ddd", nsmgr);
// nodes has 3 nodes
Note x in the above is arbitrary; there is no significance in x other than convenience.
This (rather inconveniently) means adding the namespace (or an alias, as above) into all of your xpath expressions.
Related
If I have an XML file with namespaces like:
<root>
<h:table xmlns:h="http://www.namespaces.com/namespaceOne">
<h:tr>
<h:td>Apples</h:td>
<h:td>Bananas</h:td>
</h:tr>
</h:table>
<h:table xmlns:h="https://www.namespaces.com/namespaceTwo">
<h:name>African Coffee Table</h:name>
<h:width>80</h:width>
<h:length>120</h:length>
</h:table>
</root>
I want to hoist all of the namespaces to the root element, like this:
<root xmlns:h="http://www.namespaces.com/namespaceOne" xmlns:h1="https://www.namespaces.com/namespaceTwo">
<h:table>
<h:tr>
<h:td>Apples</h:td>
<h:td>Bananas</h:td>
</h:tr>
</h:table>
<h1:table>
<h1:name>African Coffee Table</h1:name>
<h1:width>80</h1:width>
<h1:length>120</h1:length>
</h1:table>
</root>
Is there a way to do this? Ideally automatically resolving conflicting namespace prefixes, as in the example above. I haven't committed to using Linq to XML or System.Xml yet, so either would be a possibility.
There is one major constraint: because of the environment I am working in, I can't write classes. I can write functions, but no new class definitions.
Turns out this is pretty straightforward:
var doc = XDocument.Parse(xml);
var namespaceAttributes = doc.Descendants()
.SelectMany(x => x.Attributes())
.Where(x => x.IsNamespaceDeclaration);
int count = 1;
foreach (var namespaceAttribute in namespaceAttributes)
{
doc.Root.Add(new XAttribute(XNamespace.Xmlns + $"h{count}", namespaceAttribute.Value));
namespaceAttribute.Remove();
count++;
}
We loop through all namespace declarations (xmlns:foo="foo"). For each one we find, we put a namespace attribute with the same URL on the root element, and remove that one.
Demo.
Note that this does slightly odd things if you have multiple namespaces with the same URL (e.g. if you have two lots of xmlns:h="https://www.namespaces.com/namespaceOne" on different children): it puts multiple xmlns declarations on the root element with the same URL, but all elements use the last such namespace. If you want to avoid that, just keep a list of namespaces you've added to the root element.
Assume this simple XML fragment in which there may or may not be the xml declaration and has exactly one NodeElement as a root node, followed by exactly one other NodeElement, which may contain an assortment of various number of different kinds of elements.
<?xml version="1.0">
<NodeElement xmlns="xyz">
<NodeElement xmlns="">
<SomeElement></SomeElement>
</NodeElement>
</NodeElement>
How could I go about selecting the inner NodeElement and its contents without the namespace? For instance, "//*[local-name()='NodeElement/NodeElement[1]']" (and other variations I've tried) doesn't seem to yield results.
As for in general the thing that I'm really trying to accomplish is to Deserialize a fragment of a larger XML document contained in a XmlDocument. Something like the following
var doc = new XmlDocument();
doc.LoadXml(File.ReadAllText(#"trickynodefile.xml")); //ReadAllText to avoid Unicode trouble.
var n = doc.SelectSingleNode("//*[local-name()='NodeElement/NodeElement[1]']");
using(var reader = XmlReader.Create(new StringReader(n.OuterXml)))
{
var obj = new XmlSerializer(typeof(NodeElementNodeElement)).Deserialize(reader);
I believe I'm missing just the right XPath expression, which seem to be rather elusive. Any help much appreciated!
Try this:
/*/*
It selects children of the root node.
Or
/*/*[local-name() = 'NodeElement']
It selects children with local-name() = 'NodeElement' of the root node.
Anyway in your case both expressions select <NodeElement xmlns="">.
walk the tree
foreach(XmlNode node in doc.DocumentElement.childnodes[0].childnodes)
{
// do something with node
}
hideously fragile of course might want to check for nulls here and there.
<?xml version='1.0' encoding='utf-8' standalone='yes'?>
<stock-items>
<stock-item>
<name>Loader 34</name>
<sku>45GH6</sku>
<vendor>HITINANY</vendor>
<useage>Lifter 45 models B to C</useage>
<typeid>01</typeid>
<version>01</version>
<reference>33</reference>
<comments>EOL item. No Re-order</comments>
<traits>
<header>56765</header>
<site>H4</site>
<site>A6</site>
<site>V1</site>
</traits>
<type-validators>
<actions>
<endurance-tester>bake/shake</endurance-tester>
</actions>
<rules>
<results-file>Test-Results.txt</results-file>
<file-must-contain file-name="Test-Results.xml">
<search>
<term>[<![CDATA[<"TEST TYPES 23 & 49 PASSED"/>]]></term>
<search-type>exactMatch</search-type>
</search>
</file-must-contain>
</rules>
</type-validators>
</stock-item>
</stock-items>
Im trying to get the rules fragment from the xml above into a string so it can be added to a database. Currently the search element and its contents are added twice. I know why this is happing but cant figure out how to prevent it.
Heres my code
var Rules = from rules in Type.Descendants("rules")
select rules.Descendants();
StringBuilder RulesString = new StringBuilder();
foreach (var rule in Rules)
{
foreach (var item in rule)
{
RulesString.AppendLine(item.ToString());
}
}
Console.WriteLine(RulesString);
Finally any elements in rules are optional and some of these elements may or may not contain other child elements up to 4 or 5 levels deep. TIA
UPDATE:
To try and make it clearer what im trying to achieve.
From the xml above I should end up with a string containing everthing in the rules element, exactly like this:
<results-file>Test-Results.txt</results-file>
<file-must-contain file-name="Test-Results.xml">
<search>
<term>[<![CDATA[<"TEST TYPES 23 & 49 PASSED"/>]]></term>
<search-type>exactMatch</search-type>
</search>
</file-must-contain>
Objective is to extract the entire contents of the rules element as is while taking account that the rules element may or may not contains child elements several levels deep
If you just want the entirety of the rules element as a string (rather than caring about its contents as xml), you don't need to dig into its contents, you just need to get the element as an XNode and then call ToString() on it :
The following example uses this method to retrieve indented XML.
XElement xmlTree = new XElement("Root",
new XElement("Child1", 1)
);
Console.WriteLine(xmlTree);
This example produces the following output:
<Root>
<Child1>1</Child1>
</Root>
if you want to prevent duplicates than you will need to use Distinct() or GroupBy() after parsing the xml and before building the string.
I'm still not fully understanding exactly what the output should be, so I can't provide a clear solution on what exactly to use, or how, in terms of locating duplicates. If you can refine the original post that would help.
we need the structure of the xml as it would appear in your scenario. nesting and all.
we need an example of the final string.
saving it to a db doesn't really matter for this post so you only need to briefly mention that once, if at all.
If I get the path to a specific node as a string can I somehow easily find said node by using Linq/Method of the XElement ( or XDocument ).
There are so many different types of XML objects it would also be nice if as a added bonus you could point me to a guide on why/how to use different types.
EDIT: Ok after being pointed towards XPathSelectElement I'm trying it out so I can give him the right answer I can't quite get it to work though. This is the XML I'm trying out
<Product>
<Name>SomeName</Name>
<Type>SomeType</Type>
<Quantity>Alot</Quantity>
</Product>
and my code
string path = "Product/Name";
string name = xml.XPathSelectElement(path).Value;
note my string is coming from elsewhere so I guess it doesn't have to be literal ( at least in debug mode it looks like the one above). I've also tried adding / in front. It gives me a null ref.
Try using the XPathSelectElement extension method of XElement. You can pass the method an XPath expression to evaluate. For example:
XElement myElement = rootElement.XPathSelectElement("//Book[#ISBN='22542']");
Edit:
In reply to your edit, check your XPath expression. If your document only contains that small snippet then /Product/Name will work as the leading slash performs a search from the root of the document:
XElement element = document.XPathSelectElement("/Product/Name");
If there are other products and <Product> is not the root node you'll need to modify the XPath you're using.
You can also use XPathEvaluate
XDocument document = XDocument.Load("temp.xml");
var found = document.XPathEvaluate("/documents/items/item") as IEnumerable<object>;
foreach (var obj in found)
{
Console.Out.WriteLine(obj);
}
Given the following xml:
<?xml version="1.0" encoding="utf-8" ?>
<documents>
<items>
<item name="Jamie"></item>
<item name="John"></item>
</items>
</documents>
This should print the contents from the items node.
I have an xml that I would like to get all of its elements. I tried getting those elements by Descendants() or DescendantNodes(), but both of them returned me repeated nodes
For example, here is my xml:
<Root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<FirstElement xsi:type="myType">
<SecondElement>A</SecondElement>
</FirstElement>
</Root>
and when I use this snippet:
XElement Elements = XElement.Parse(XML);
IEnumerable<XElement> xElement = Elements.Descendants();
IEnumerable<XNode> xNodes = Elements.DescendantNodes();
foreach (XNode node in xNodes )
{
stringBuilder.Append(node);
}
it gives me two nodes but repeating the <SecondElement>. I know Descendants call its children, and children of a child all the time, but is there any other way to avoid it?
Then, this is the content of my stringBuilder:
<FirstElement xsi:type="myType" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<SecondElement>A</SecondElement>
</FirstElement>
<SecondElement>A</SecondElement>
Well do you actually want all the descendants or just the top-level elements? If you only want the top level ones, then use the Elements() method - that returns all the elements directly under the current node.
The problem isn't that nodes are being repeated - it's that the higher-level nodes include the lower level nodes. So the higher-level node is being returned, then the lower-level one, and you're writing out the whole of both of those nodes, which means you're writing out the lower-level node twice.
If you just write out, say, the name of the node you're looking at, you won't see a problem. But you haven't said what you're really trying to do, so I don't know if that helps...
XmlDocument doc = new XmlDocument();
doc.LoadXml(XML);
XmlNodeList allElements = doc.SelectNodes("//*");
foreach(XmlElement element in allElements)
{
// your code here
}