I get a XML - File like this:
<list>
<sublist id1="a" id2="b" id3="b" id4="b">
<item name="name1">
<property1>a</property1>
</item>
<item2 name="name2">
<property1>c</property1>
</item2>
</sublist>
<sublist id1="b" id2="b" id3="a" id4="b">
[...more XML here...]
</sublist>
How can I find out the attribute name of the element "sublist" with the value "a" ?
If you have the XML string in a variable called xml:
XDocument
.Parse(xml) // parse the XML
.Descendants() // get all descendant elements
.SelectMany(e => e.Attributes()) // get all attributes from all elements
.Where(a => a.Value == "a") // leave only attributes whose value is "a"
.Select(a => a.Name); // select the name of those attributes
The result:
id1
id3
Note that this code uses XElement and LINQ to accomplish the goal. There are many other ways, some of which may be better suited to your needs.
Update
I noticed now that you're only looking for attributes on sublist elements. The code can be modified to handle that:
XDocument
.Parse(xml) // parse the XML
.Descendants("sublist") // get all descendant elements named "sublist"
.SelectMany(e => e.Attributes()) // get all attributes from all elements
.Where(a => a.Value == "a") // leave only attributes whose value is "a"
.Select(a => a.Name); // select the name of those attributes
The difference is in the call to Descendants, which now filters out any elements that is not called sublist.
In a comment you also asked how to handle the case when there is just a single sublist element. The code snippets above work fine for that too, since they're not making any assumptions about the number of elements.
You might be tempted to handle that case differently, such as with this code:
XDocument
.Parse(xml) // parse the XML
.Descendants("sublist") // get all descendant elements named sublist
.Single() // get the one and only element
.Attributes() // get all attributes from all elements
.Where(a => a.Value == "a") // leave only attributes whose value is "a"
.Select(a => a.Name) // select the name of those attributes
The difference between this and the previous examples is that we use Single here to extract the one and only sublist element from the result. The item type in the code at that point becomes XElement, and Single will throw an exception if there are no ("Sequence contains no elements") or more than one ("Sequence contains more than one element") sublist elements. In the next line we can then get rid of the SelectMany call and just access the Attributes of the XElement straight away.
But in my opinion the change in the code is not worth the loss in robustness you'll have.
Related
Since I am not very familiar with LINQ and xDocument, I struggle to implement the following:
I have a XML file which looks like
<document>
<attribut1/>
<attribut2>
<house price="100" location="UK" id-ext="Id-100"/>
<house price="300" location="GB" id-int="Id-101"/>
</attribut2>
<attribut3/>
</document>
Speaking in Pseudo Code I need something like
Input: xDocument
Output: List containing strings with all values, i.e. "Id-100" in this example, of those attributes where "id-ext" was included in the attribut name. Hence, I try to get the values of those attributes which contain some certain letters in their name.
I already searched for similar suggestions like the one stated here:
How to search entire XML file for keyword?
But the point is that here the whole XML-Node is returned and I don't manage to break it down to the name of an attribute.
I would appreciate any suggestions of how to move one after applying "Descendants" to get the values of those attributs where some keywords are contained in the attribut name.
Use a dictionary
XDocument doc = XDocument.Load(FILENAME);
Dictionary<string, List<XElement>> dict = doc.Descendants("house")
.Where(x => x.Attribute("id-ext") != null)
.GroupBy(x => (string)x.Attribute("id-ext"))
.ToDictionary(x => x.Key, y => y.ToList());
Assuming "keywords are contained in the attribut name" means that the attribute name as a string contains a specific substring, and that this attribute may occur on any element in the document:
var doc = XDocument.Parse(#"<document>
<attribut1/>
<attribut2>
<house price='100' location='UK' id-ext='Id-100'/>
<house price='300' location='GB' id-int='Id-101'/>
</attribut2>
<attribut3/>
</document>");
foreach (var s in doc
.Descendants()
.SelectMany(e => e.Attributes())
.Where(a => a.Name.LocalName.Contains("id-ext"))
.Select(a => a.Value))
{
Console.WriteLine(s);
}
So lets say I have a XElement that looks something like this
<Root>
<ProductOne>
<Size>Large</Size>
<Height>2</Height>
</ProductOne>
<ProductTwo>
<Size>Small</Size>
<Type>Bar</Type>
</ProductOne>
<ProductThree>
<Size>Small</Size>
<Type>Crate</Type>
<Color>Blue</Color>
</ProductOne>
<SomeOtherStuff>
<OtherThing>CrazyData</OtherThing>
</SomeOtherStuff>
</Root>
I want to query this data and get a IEnumerable string of the child values (I.E. Size, Type, Color, and a lot of other possuble attributes) of anything that is in a element with the word "Product" in it.
So My resulting list would look like
Large
2
Small
Bar
Small
Crate
Blue
Could someone tell me how to construct such a query using LINQ?
First, you have a lot of typos with your xml. Here is the correct version:
var xml = #"
<Root>
<ProductOne>
<Size>Large</Size>
<Height>2</Height>
</ProductOne>
<ProductTwo>
<Size>Small</Size>
<Type>Bar</Type>
</ProductTwo>
<ProductThree>
<Size>Small</Size>
<Type>Crate</Type>
<Color>Blue</Color>
</ProductThree>
<SomeOtherStuff>
<OtherThing>CrazyData</OtherThing>
</SomeOtherStuff>
</Root>";
Now, here is some linq magic you can do to get the values you want.
var list = XElement.Parse(xml) //parses the xml as an XElement
.Elements() //gets all elements under the "root" node
.Where(x => x.Name.LocalName.StartsWith("Product")) // only selects elements that
// start with "product"
.SelectMany(x => x.Elements()) // inside of each of the "product" nodes, select
// all the inner nodes and flatten the results
// into a single list
.Select(x => x.Value) //select the node's inner text
.ToList(); //to list (optional)
This will give you back your wanted list as a List<string>.
Large
2
Small
Bar
Small
Crate
Blue
I have a large, messy XML file and I want to retrieve ALL elements of the same name ("Item" for the sake of this post) from it, then be able to retrieve data from each element's children.
So far I have returned a list of every element called "Item" using this code, which just displays the namespace url and "Item" in p tags:
XDocument doc = XDocument.Load(#"C:\inetpub\wwwroot\mysite\myxml.xml");
XNamespace ns = "http://www.mynamespace.com";
var nodes = doc.Descendants().Elements(ns + "Item").Select(d => d.Name).ToList();
foreach(var x in nodes){
<p>#x</p>
}
However, by amending the code with the following, I can't retrieve any data of it's children and I get the error 'System.Xml.Linq.XName' does not contain a definition for 'Descendants':
foreach(var x in nodes){
<p>#x.Descendants().Element("Name")</p>
}
Here is a very basic version of my XML file:
<Item>
<Name>Item 1</Name>
<Type>Type 1</Type>
</Item>
I want to be able to search each 'Item' element for a 'Name' element and return the value. Can anyone see where I'm going wrong?
This is the problem:
.Select(d => d.Name)
You're explicitly selecting the names of the elements. If you want the actual elements (which I think you do), just get rid of that call:
var nodes = doc.Descendants().Elements(ns + "Item").ToList();
You could also get rid of the ToList() unless you need the query to be materialized eagerly.
If I have a simple XML document such as
<case id="37d3c93c-3201-4002-b24f-08e1221c3cb7">
<party id="26dad8c5-9487-48f2-8911-1d78c00095b2">...</party>
<illustration CaseId="37d3c93c-3201-4002-b24f-08e1221c3cb7">....</illustration>
<illustration CaseId="37d3c93c-3201-4002-b24f-08e1221c3cb7">....</illustration>
<item relatedCaseId="37d3c93c-3201-4002-b24f-08e1221c3cb7">...</illustration>
</case>
I have code that changes the id attribute of the case element. I am now looking for some LINQ code that would help me search all elements that have an attribute value that matches the old value so I can replace it with the new value. I do not have a list of attribute names, and would need to search the entire document.
Any tips/ideas?
Thanks!
Something like this:
var matches = doc.Descendants()
.Where(x => x.Attributes()
.Any(attr => attr.Value == oldValue));
Or if you're just trying to replace the values, you only need the attributes themselves:
var attributes = doc.Descendants()
.Attributes()
.Where(attr => attr.Value == oldValue)
.ToList();
foreach (var attribute in attributes)
{
attribute.Value = newValue;
}
It's entirely possible that the copy to a list isn't necessary in this case, but I generally prefer to make a copy when mutating an XDocument to avoid confusing things. (It's certainly necessary when you're removing an element or something like that - just setting the value of an attribute probably doesn't affect things.)
Trying to use
exportDoc.Root.Elements("string").Where(node => !(node.Element("product").HasElements) || node.Element("product").Element("type").Value != product).Remove();
to remove the nodes in my XML document where the product string I'm searching for doesn't occur. Here is a sample of my XML structure:
<root>
<string id = "Hithere">
<product>
<type>orange</type>
<type>yellow</type>
<type>green</type>
<product>
<element2/>
<element3/>
</string>
<string id ="...">
...
...
</root>
So I need to look under the product element of each string element AND at each of the type elements therein to see if the value of string product (input to the method where this is contained) occurs. At present, it looks like my code only removes the node if the product string I'm searching for matches the value of just the first type element.
The whole point is to remove all string nodes from this xdoc that don't have the product I'm looking for listed under their product element.
You need to change your search condition slightly:
var nodesToRemove = xDoc.Root
.Elements("string")
.Where(node =>
!(node.Element("product").HasElements) ||
node.Element("product").Elements("type").All(x => x.Value != product))
.ToList();
This should match elements which all string:product:types differ from product value (or in other words - if at least one <type> will match your product, it won't be marked for removal).
You can't Remove() while you're still enumerating (deferred execution).
You need something more like:
// untested
var toRemove = exportDoc.Root.Elements("string")
.Where(node => !(node.Element("product").HasElements) ||
node.Element("product").Element("type").Value != product).ToList();
toRemove.Remove();