C# Linq to XML, get parents when a child satisfy condition

Question

I need some help. I have this xml document:

<?xml version="1.0" encoding="utf-8"?>
<MyItems>
    <Parent upc="A00000000000000000000001" sku="" archivo="pantalon1.jpg">
        <Child upc="101" sku="" archivo="image##.jpg">
            <GrandChild archivo="image##.jpg" />
        </Child>
        <Child upc="102" sku="" archivo="image##.jpg">
            <GrandChild archivo="image##.jpg" />
        </Child>
    </Parent>
    <Parent upc="A00000000000000000000002" sku="" archivo="image##.jpg">
        <Child upc="101" sku="" archivo="image##.jpg">
            <GrandChild archivo="image##.jpg" />
        </Child>
        <Child upc="102" sku="" archivo="image##.jpg">
            <GrandChild archivo="image##.jpg" />
        </Child>
    </Parent>
    <Parent upc="200" sku="" archivo="image##.jpg">
        <Child upc="201" sku="" archivo="image##.jpg">
            <GrandChild archivo="image##.jpg" />
        </Child>
        <Child upc="202" sku="" archivo="image##.jpg">
            <GrandChild archivo="image##.jpg" />
        </Child>
    </Parent>
</MyItems>

Then, I'm trying to select all the 'Parents' where a 'Child' fulfils a condition. Example, all the parents which contains a child where, child attribute upc is equal to 101

I was studying this article: Select nodes based on properties of descendant nodes

But I just can't get what I want.

Answer 1

XDocument doc = ...;
var targetUpc = 101;
var query = doc.Descendants("Parent")
    .Where(p => p.Elements("Child")
                 .Any(c => (int)c.Attribute("upc") == targetUpc)
    );

So what the query does is select all descendant elements named Parent where any of its child elements named Child have an attribute named upc that is equal to the target upc value, targetUpc. Hopefully you should be able to follow that.

Answer 2

Use a Where with a nested Any.

var xml = XElement.Parse(yourString);
var result = xml.Elements("Parent").Where(parent => 
    parent.Elements("Child").Any(child => child.Attribute("upc").Value == "101"));