c# - How do I remove a child element based on attributes on multiple parents? -

i have xml file similar structure below:

<?xml version="1.0" encoding="utf-8"?> <root attr1="foo" name="myname" attr2="bar" >     <parent1 name="is">         <child1 name="kronos1">             <grandchild1 name="word_1"/>             <grandchild2 name="word_2"/>             <grandchild3 name="word_3"/>             <grandchild4 name="word_4"/>         </child1>         <child2 name="kronos2">             <grandchild1 name="word_1"/>             <grandchild2 name="word_2"/>             <grandchild3 name="word_3"/>             <grandchild4 name="word_4"/>         </child2>     </parent1> </root> 

the elements not defined in can have different values other files. know "name" attribute of each element before hand, defined. need able manipulate, and/or delete data within selected element based on name. example: removeelement("myname.is.kronos1.word_1") delete grandchild1 element underneath child1 parent.

my issues while using linq xml queries i'm not able select element properly. using this:

private ienumerable<xelement> findelements(ienumerable<xelement> docelements, string[] names) {     // string[] array desired element removed.     // i.e. my.name.is ==> array[ "my, "name", "is"]     ienumerable<xelement> currentselection = docelements.descendants();      foreach (string name in names)     {         currentselection =             el in currentselection             el.attribute("name").value == name             select el;     }      return currentselection;  } 

to find need remove elements yields result:

<?xml version="1.0" encoding="utf-8"?> <root attr1="foo" name="myname" attr2="bar" >     <parent1 name="is">         <child1 name="kronos1">             <grandchild2 name="word_2"/>             <grandchild3 name="word_3"/>             <grandchild4 name="word_4"/>         </child1>         <child2 name="kronos2">             <grandchild2 name="word_2"/>             <grandchild3 name="word_3"/>             <grandchild4 name="word_4"/>         </child2>     </parent1> </root> 

after debugging appears i'm doing searching same document on again, different names each time. how search , select specific element based on multiple parent attribute names?

it should noted, size of xml (meaning levels of elements) variable. meaning there can little 2 levels (parents) or 6 levels (great-great-grandchildren). however, need able @ root node's name attribute well.

this should work:

if (doc.root.attribute("name").value != names.first())     throw new invalidoperationexception("sequence contains no matching element.");  var selection = doc.root;  foreach (var next in names.skip(1))     selection = selection.elements().first(x => x.attribute("name").value == next);  return selection; 

you can replace latest lines following if want to:

var selection = names.skip(1).aggregate(doc.root, (current, next) => current.elements().first(x => x.attribute("name").value == next)); 

the .first() method throws exception if no matching element found in source.

---

the cleanest approach add new function:

xelement selectchildelement(xelement current, string child) {     if (current == null)         return null;              var elements = current.elements();     return elements.firstordefault(x => x.attribute("name").value == child); } 

such can use following:

if (doc.root.attribute("name").value != names.first())     return null;  return names.skip(1).aggregate(doc.root, selectchildelement); 

and then, if ever need select 1 child, have handy selectchildelement() avaialble. if want myelement.selectchild(child) instead, can call extension.

also, use firstordefault here, don't exception null returned instead.

this way, doesn't have keep track of exceptions more costly...