Finding element in XDocument

Question

I have a simple XML   lt AllBands gt     lt Band gt       lt Beatles ID  1234  started  1962  gt greatest Band lt   CDATA lalala   gt  lt  Beatles gt       lt Last gt 1 lt  Last gt       lt Salary gt 2 lt  Salary gt     lt  Band gt     lt Band gt       lt Doors ID  222  started  1968  gt regular Band lt   CDATA lalala   gt  lt  Doors gt       lt Last gt 1 lt  Last gt       lt Salary gt 2 lt  Salary gt     lt  Band gt   lt  AllBands gt    However     when I want to reach the  Doors band  and to change its ID       using  var stream   new StringReader result                                 XDocument xmlFile   XDocument Load stream                    var query   from c in xmlFile Elements  Band                                select c                                     query has no results  But  If I write  xmlFile Elements   Elements  Band   so it Does find it   What is the problem    Is the full path from the Root needed    And if so   Why did it work without specify AllBands    Does the XDocument Navigation require me to know the full level structure down to the required element

User · Answer

My experience when working with large  amp  complicated XML files is that sometimes neither Elements nor Descendants seem to work in retrieving a specific Element  and I still do not know why     In such cases  I found that a much safer option is to manually search for the Element  as described by the following MSDN post   https   social msdn microsoft com Forums vstudio en-US 3d457c3b-292c-49e1-9fd4-9b6a950f9010 how-to-get-tag-name-of-xml-by-using-xdocument forum csharpgeneral  In short  you can create a GetElement function   private XElement GetElement XDocument doc string elementName        foreach  XNode node in doc DescendantNodes                  if  node is XElement                        XElement element    XElement node              if  element Name LocalName Equals elementName                   return element                      return null      Which you can then call like this   XElement element   GetElement doc  Band      Note that this will return null if no matching element is found

User · Answer

You should use Root to refer to the root element   xmlFile Root Elements  Band     If you want to find elements anywhere in the document use Descendants instead   xmlFile Descendants  Band

User · Answer

The Elements   method returns an IEnumerable lt XElement gt  containing all child elements of the current node   For an XDocument  that collection only contains the Root element   Therefore the following is required   var query   from c in xmlFile Root Elements  Band               select c

User · Answer

The problem is that Elements only takes the direct child elements of whatever you call it on  If you want all descendants  use the Descendants method   var query   from c in xmlFile Descendants  Band

User · Answer

Elements   will only check direct children - which in the first case is the root element  in the second case children of the root element  hence you get a match in the second case  If you just want any matching descendant use Descendants   instead   var query   from c in xmlFile Descendants  Band   select c    Also I would suggest you re-structure your Xml  The band name should be an attribute or element value  not the element name itself - this makes querying  and schema validation for that matter  much harder  i e  something like this    lt Band gt     lt BandProperties Name   Doors  ID  222  started  1968    gt     lt Description gt regular Band lt   CDATA lalala   gt  lt  Description gt     lt Last gt 1 lt  Last gt     lt Salary gt 2 lt  Salary gt   lt  Band gt

User · Answer

You can do it this way   xml Descendants   SingleOrDefault p   gt  p Name LocalName     Name of the node to find     where xml is a XDocument   Be aware that the property Name returns an object that has a LocalName and a Namespace  That s why you have to use Name LocalName if you want to compare by name

User · Answer

Sebastian s answer was the only answer that worked for me while examining a xaml document  If  like me  you d like a list of all the elements then the method would look a lot like Sebastian s answer above but just returning a list         private static List lt XElement gt  GetElements XDocument doc  string elementName                List lt XElement gt  elements   new List lt XElement gt              foreach  XNode node in doc DescendantNodes                          if  node is XElement                                XElement element    XElement node                  if  element Name LocalName Equals elementName                       elements Add element                                   return elements          Call it thus   var elements   GetElements xamlFile   Band      or in the case of my xaml doc where I wanted all the TextBlocks  call it thus   var elements   GetElements xamlFile   TextBlock

[c#] Finding element in XDocument?

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