linq to XML: multiple node/value queries in a document

ezazazel

Hi again! Qnother question comes to my mind and since this is the best place to get an answer, I'm trying it here (hey, that's been a compliment!). So I can query a node/value combination from a XML file:

public FileInfo ReadXML(FileInfo fInfo, string node, string value) {
XDocument xmlFile = XDocument.Load(fInfo.FullName);
var query = (from p in xmlFile.Descendants(node)
where p.Value.Contains(value)
select p).ToArray();
if (query.Count() != 0)
return fInfo; }

but how this should look like if I have for instance two node/value combinations I have to query for. E.g: Name has to be Franz AND he needs to be born in Canada Name has to be either Franz or the Person has to be born in CANADA As always thanks in advance, eza (this is a double post, but I missed this forum in the first place)

Howard Richards

In this case you cannot look at the individual descendants but you need to search the "parent" nodes individually, and then query their descendants. Example: given the file

<?xml version="1.0" encoding="utf-8" ?>
<people>
<person>
<name>Franz</name>
<country>Canada</country>
</person>
<person>
<name>Franz</name>
<country>Germany</country>
</person>
<person>
<name>Bob</name>
<country>Canada</country>
</person>
<person>
<name>Mike</name>
<country>UK</country>
</person>
<person>
<name>Alan</name>
<country>Germany</country>
</person>
</people>

First you build a list of the "person" node to get the 'container'. Then you can do a sub-query on each node, looking for the child elements.

        var doc = XDocument.Load("XMLFile1.xml");

        // select the nodes of type person
        var nodes = from n in doc.Descendants("person") select n;

        // get EITHER Franz or Canada
        var FranzORCanada = from n in nodes
                            where ((from x in n.Descendants("name") where x.Value == "Franz" select x).Count() > 0)
                            || ((from y in n.Descendants("country") where y.Value == "Canada" select y).Count() > 0)
                            select n;

        Console.WriteLine("FRANZ or CANADA");
        Console.WriteLine("---------------");
        foreach (var node in FranzORCanada)
        {
            Console.WriteLine("{0} - {1}", node.Descendants("name").First().Value, node.Descendants("country").First().Value);
        }
        Console.WriteLine();

        // get nodes with Franz AND Canada
        var FranzANDCanada = from n in nodes
                             where ((from x in n.Descendants("name") where x.Value == "Franz" select x).Count() > 0)
                            && ((from y in n.Descendants("country") where y.Value == "Canada" select y).Count() > 0)
                            select n;

        Console.WriteLine("FRANZ and CANADA");
        Console.WriteLine("----------------");
        foreach (var node in FranzANDCanada)
        {
            Console.WriteLine("{0} - {1}", node.Descendants("name").Fir

ezazazel

Thank you for your excelent solution.